Title: An account of a useful discovery to distill double the usual quantity of seawater
Author: Hales, Stephen
Language: English
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DISCOVERY TO DISTILL DOUBLE THE USUAL QUANTITY OF SEAWATER ***



 AN
 ACCOUNT
 OF A
 USEFUL DISCOVERY
 TO

 Distill double the usual Quantity of Sea-Water,
 by blowing Showers of Air up through the Distilling Liquor:

AND

An Account of the great Benefit of Ventilators in many Instances, in
preserving the Health and Lives of People, in Slave and other Transport
Ships, which were read before the _Royal Society_.

ALSO

An Account of the good Effect of blowing Showers of Air up through
Milk, thereby to cure the ill Taste which is occasioned by some Kinds
of Food of Cows.

       *       *       *       *       *

  By _STEPHEN HALES_, D.D.F.R.S.

  Member of the Royal Academy of Sciences at _Paris_,
  AND
  Clerk of the Closet to Her Royal Highness the
  Princess of _Wales_.

         *       *       *       *       *

  _The_ Second Edition.

         *       *       *       *       *

  With an _APPENDIX_;

 In which is an Account of some farther considerable Improvements made
 in the Method of procuring Plenty of Fresh-Water at Sea, _viz._ three
 Parts in four more than in the common Methods of Distilling: Also a
 farther Account of more Instances and Proofs of the good Effect of
 Ventilators in Ships: As also of the curing, in a few Minutes, the ill
 Taste of Turnip Milk, and of musty Liquors. Also, with great Ease,
 presently to make Cream or Milk Sillabubs, _viz._ by blowing Showers
 of Air up through them.

       *       *       *       *       *

 _LONDON_:
 Printed for Richard Manby, in the _Old-Bailey_,
 near _Ludgate-Hill_. M.DCC.LVI.



AN ACCOUNT OF THE

 Great Benefit of blowing Showers of Fresh Air
 up thro’ Distilling Liquors.


1. The great Importance of having a sufficient Supply of fresh Water
in Ships, has been the Occasion of many laudable Attempts to make
Sea-water fresh and wholsome; but all the Attempts and Discoveries
hitherto made, have laboured under this great and material Objection,
_viz._ the great Quantity of Fuel that was necessary to distill,
with a slow Progress, a small Quantity of Water, by any Methods
of Distillation hitherto known. But I have lately happily, most
unexpectedly, discovered an easy and effectual Method to distill
great Quantities of Water with little Fuel; which I was led to by the
following Incidents, _viz._ Mr. _Shipley_, Secretary of our Society,
_for the Encouragement of Arts, Manufactures and Commerce_, brought me
acquainted with Mr. _William Baily_ of _Salisbury-Court_, the Author of
many ingenious Contrivances; who shewed me, in a small Model of a Tin
Vessel, a Method, by which he has happily increased the Force of the
Engine to raise Water by Fire, _viz._ by lifting up some of the boiling
Water, at every Stroke, by means of a conical Vessel, with small Holes
in it, full of Tow; whereby the Quantity of the ascending Steam or
Wreak was considerably increased. This led me to think, that a greater
Quantity of Liquor might also by this Means be distilled; but on Trial
I found the Increase to be only one twelfth Part, tho’ considerable
in the expanded Form of a Steam. Hence I was led to try what would
be the Effect of causing an incessant Shower of Air to ascend thro’
the boiling Liquor in a Still; and this, to my Surprise, I found on
Trial to be very considerable. There was another Circumstance also,
which probably conduced to lead my Mind to this Thought, _viz._ About
six Months before, Mr. _Littlewood_, a Shipwright at _Chatham_, came
thence purposely to communicate to me an ingenious Contrivance of his,
soon to sweeten stinking Water, by blowing a Shower of fresh Air thro’
a Tin Pipe full of small Holes, layed at the Bottom of the Water. By
this means, he told me, he had sweetened the stinking Bilge Water in
the Well of some Ships; and also a But of stinking Water in an
Hour, in the same manner as I blew Air up thro’ Corn and Gunpowder, as
mentioned in the Book on _Ventilators_.

2. The Method, which I used to blow Showers of Air up thro’ the
distilling Water, was by means of a flat round Tin Box, six Inches
Diameter, and an Inch and half deep; which is placed at the Bottom
of the Still, on four Knobs or Feet half Inch high, to make room for
the Liquor to spread over the whole Bottom of the Still, that the
Heat of the Fire may come at it. In larger Stills this Box must be
proportionably larger, and have higher Feet. And whereas the Mouth of
the Still is too narrow, for the Tin Box to enter, which Box ought to
be within two Inches as wide as the Bottom of the Still; therefore the
Box may be divided into two Parts, with a Hinge at one Edge or Side,
and a Clasp at the other, to fix it together, when in the Still. This
Box must be of Copper for distilling Sea-water; mine was made of Tin
for other Liquors also. The Air-pipe, which passes thro’ the Head of
the Still, will help to keep the Air-box from moving to and fro by
the Motion of the Ship; or, if that should not be found sufficient, 3
or 4 small Struts may be fixed to the Sides of the Air-box. They must
reach to the Sides of the Still. The Cover and Sides of the Air-box
were punched full of very small Holes, one-fourth Inch distant from
each other, and about the twentieth part of an Inch in Diameter. On
the Middle of the Cover or Lid of this Air-box, was fixed a Nosil more
than half Inch wide, which was fitted to receive, to put on, and take
off the lower End of a Tin Pipe, which was twenty Inches long, and
passed thro’ a Hole in the Head of the Still: four Inches of the upper
end of this Pipe were bent to a Crook, almost at a right Angle to the
upright Stem, in order thereby to unite the Crook to the widened Nose
of a Pair of Kitchen double Bellows, by means of a short Leathern Pipe
of Calves-skin. See Fig. 1st. This Tin Air-box, and many more of them
for other Persons, were made by Mr. _Tedway_, Tinman, over-against the
_Meuse-Gate_, _Charing-Cross_.

3. The double Bellows were bound fast to a Frame, at the upper Part of
the Iron Nose, and at the lower Handle, in order the more commodiously
to work them. And that the upper Half of the double Bellows may duly
rise and fall, in order to cause a constant Stream of Air; (besides
the usual contracting spiral Springs within side) several flat Weights
of Lead must be layed on the upper Part of the Bellows, near the
Handle, with a Hole in their Middle, to fix them on an upright Iron Pin
fastened on the Bellows: That by this Means the Weights may the more
commodiously be put on or taken off. For, according to the different
Depths of the Liquor in the Still, so will the Force of the included
Air, against the upper Board of the Bellows, be more or less. Thus,
supposing the Depth of the Water in the Still to be twelve Inches; from
the Surface of the depressed Water in the Air-Box; then the Pressure
of the included Air against the upper Part of the Bellows, will be
equal to that of a Body of Water a Foot deep, and as broad as the inner
Surface of that Board. It will, therefore, be requisite, to add or take
off Weights, according to the different Depths of the Water in the
Still, at different Periods of the same Distillation. The Bellows must
be proportionable to the Size of the Still, but need not be very large.
Wherever the Stills are fixed in Ships, the Air may be conveyed to them
from the Bellows, either thro’ a small leathern Pipe, distended with
Spiral Coiles of Wyre, or thro’ Bamboo Canes, or broad small wooden
Pipes, like hollow fishing Rods.

4. When I first distilled in this ventilating Way, in order to
estimate, what the Difference might be in the Quantity distilled,
by that or the common Method, I tried both Ways, by receiving the
distilled Liquor into a Quarter of a Pint Glass, estimating the Times,
by a Pendulum beating Seconds. Where I found, to my Surprise, that
sometimes three times more was distilled by Ventilation than by the
usual Way: But finding Inequalities in the small Quantities thus
distilled, in order the more fully and assuredly to ascertain the
true Proportion there was in the two Methods of distilling, I put
three Gallons of Water into the Still; and, when it boiled, put on the
Still-head, and fixed its Nose to the Worm-tub Pipe; which Tub was full
of cold Water. When it had distilled for an Hour, the Receiver was
instantly taken away. And on measuring the distilled Water, found it
to be two Quarts and 45 cubick Inches by a Glass divided into cubick
Inches. And a Gallon containing 282 cubick or solid Inches, this
Quantity of distilled Water, which was 186 cubick Inches, is 1/1.5 th
Part of a Gallon.

5. Then, filling the Still as full of Water as before, and when it
began to boil, fixing the Head to the Still and Worm-tub, which was
full of cold Water; there was distilled in an Hour, with constantly
blowing Showers of fresh Air up thro’ the stilling Liquors, five
Quarts, less by seven cubick Inches, which is 345.5ths cubick Inches;
that is, little less than the double of the Quantity that is distilled
in the usual Way. In several other Distillations of a Quart at a Time,
I found the Quantity distilled by Ventilation, to be more than the
double of that in the usual Way. So that the Quantity by Ventilation,
may at a Medium be estimated the double of the usual Distillation. It
is the well known Property of moving Air, to carry along with it a
considerable Quantity of adjoining Vapour, as also of falling Water to
carry much Air down along with it.

6. It is to be hoped therefore, that so considerable an Increase in the
Quantity distilled, will be of great Benefit to Navigation, as it may
be done in less Time and with less Fire.

7. In the Account of Mr. _Appleby_’s Process, for making Sea-water
fresh, which is published by Order of the Lords of the Admiralty in the
Gazette of _Jan. 22, 1754_, it is said that a Still which contains 20
Gallons of Water will distill 60 Gallons in ten Hours with little more
than one Bushel of Coals; and therefore 120 Gallons in 20 Hours, with
little more than two Bushels of Coals. And by Ventilation 240 Gallons,
or a Tun; and 24 Gallons may be distilled in twenty Hours, making an
Allowance for the times of heating those Stills full of cold Water; and
a Still something larger and wider, will distill a Tun in 24 Hours;
which will more than suffice for a sixty Gun Ship with 400 Men, whose
Provision of Water for four Months is about 110 Tuns. And larger Ships
may either have proportionably larger Stills, or else two of them. As
for Merchant-Ships with few Men, a small Still will be sufficient.

8. The second sized Stills contain 10 Gallons, and will produce 60
Gallons in 20 Hours, with half the above-mentioned Fuel; and by
Ventilation 120 Gallons.

9. The least Stills contain five Gallons, and will produce 32 Gallons
in 20 Hours; and by Ventilation 64 Gallons in 20 Hours.

10. I have seen some of these Stills at Messrs. _Steel_ and _Stephens_,
over-against _Mercers-Chapel_, in _Cheapside_, which have been made for
this Purpose. There are Holes in the Feet of the Iron Frame or Stove to
skrew them down to the Deck. They were fixed at the Fore-castle before
the Mast in King _Charles_ the Second’s time, when they thought they
had discovered the Way to distill Sea-water, free from the noxious
Spirit of Salt, and from the nauseous bittern Taste. Or, if it be
thought proper, one Part of the Ship’s Boiler may be made use of, by
adapting a Still-head to it.

11. Now supposing a Still to contain 25 Gallons, and that four Parts
in five of it, _viz._ 20 Gallons are distilled off: then, in order to
distill _a Tun_, or 210 _Gallons_, the Still must be emptied, cleansed
and refilled eleven times; and if the whole be done in 24 Hours, full
16 of those Hours will be taken up in distilling at the rate of a
Gallon in about four Minutes and half; and the remaining eight Hours
of the 24, being divided into 11 equal Parts, they will be each near
44 Minutes to empty and cleanse the Still, to refill it, and give the
Sea-water a proper boiling distilling Heat: whether this can be done in
so short a Time, must be known by Experience, and ought therefore first
to be tried at Land.

12. Doctor _Butler_, in his lately published Method of _procuring Fresh
Water at Sea_, proposes the pouring in more Sea-water into the Still,
thro’ a Funnel fixed in a small Hole in the Head or Upper-part of the
Still, when more than half the former Water is distilled off; by which
means the Water in the Still will soon acquire a distilling Heat; and
this to be repeated several times; but then it will be requisite to add
each time more Chalk, in such Proportion as shall be found requisite.
It will be well to try this Method in hopes thereby to increase
the Quantity of Water that is distilled. The Hole in the Head, or
Upper-part of the Still, is to be stopped with a small Plate of Copper,
so fixed as to turn to and fro over the Hole.

13. Doctor _Butler_ used capital Soap Lees, in the Proportion of a Wine
Quart to 15 Gallons of Sea-water, which sufficed for four or five times
repeated Pourings in of more Sea-water into the Still. But as I have
found that a small Quantity of Chalk has the same good Effect, and is
cheaper, and more easily to be had, it is therefore preferable to Soap
Lees.

14. When there is a Fire in the Cook-room, the Sea-water might be ready
heated to put into the Still, without any additional Expence of Fuel,
in the following Manner, which I shall here describe; tho’ I think
it probable that it will not be put in practice; yet, as farther
Improvements may possibly hereafter be made in it, and as it may be of
use in some Cases, at Land at least, I shall here give an Account of
it, _viz._

15. About the Year 1718, Mr. _Schmetou_ a _German_ Gentleman, got a
Patent here for heating great Quantities of Water, with little Expence
of Fuel, which he then shewed me. Having fixed a spiral Iron Worm-pipe,
in such a Brick Stove or Chimney as Women heat their Irons in, thereby
causing the Water to run from a Vessel, thro’ the Worm-pipe, several
Feet Length round, in the Fire. About 30 Years after I acquainted
Mr. _Cramond_ of _Twickenham_ with this, as hoping it might be of
Benefit in distilling Sea-water. Upon which he procured such a spiral
Iron Worm-pipe, which was about twenty Feet long, and six-tenths Inch
Diameter; the Diameter of the spiral Coile was about fourteen Inches.

16. This I fixed in a Brick Stove in my Garden, with its upper End
fixed to a Vessel, which contained 45 Gallons of Water. I found the
Event of this first Trial to be as follows, _viz._ When the Water run
full Bore, at the rate of a Gallon in 17 Seconds, the Heat of the Water
was found, by a mercurial Thermometer held in the Stream, at the lower
End of the Pipe, to be 80 Degrees above the freezing Point, 180 Degrees
being the Heat of boiling Water. When by means of a Turn-cock, a Gallon
of Water was two Minutes in running, then the Heat was 140. At which
Rate the 45 Gallons would be an Hour and half in running thro’ the
Iron-pipe; at which Rate 25 Gallons will run thro’ in 50 Minutes, with
so considerable a Degree of Heat; and if it was an Hour running, the
Heat would approach still nearer to a boiling Heat, when first put into
the Still, which would forward the Distillation if wanted.

17. I pumped the heated Water up again into the upper Vessel; and
thus continued to circulate the heating Water, till its Heat was 160
Degrees in the upper Vessel, _viz._ within 20 Degrees, or one-ninth of
boiling, the Heat requisite for plentiful Distillation. I was in hopes
that if the Water in the upper Vessel could have been brought to a due
Degree of Heat, and a Still-head were fixed on it, with its cooling
Worm-tub, then Water might have been distilled in Ships, by having the
Iron Worm-pipe fixed in the Chimney of the Cook-room: But I found,
that when the Heat of the Water in the upper Vessel was 160 Degrees,
_viz._ within one-ninth of boiling; then in running through the Iron
Worm-pipe again, it was so over-heated, as to expand in the Pipe,
into an explosive Vapour, which hindered the running of the Water.
However I thought it not improper to give an Account of this Attempt,
notwithstanding it failed. Not knowing whether this Method of heating
Water, may not in some Cases, at Land at least, be of use, thereby to
save, in some degree, both Fuel and Time: Perhaps an Iron Worm-pipe of
a larger Bore might do better.

18. The Waste of Fuel will be less in proportion to the Quantity
distilled in large, than in small Stills; and the wider the Still-head
is, so much the more Liquor will be distilled, and more with a Worm-tub
than without it. The Worm-tub may be so covered, as to prevent the
flowing over of the Water by the Motion of the Ship.

19. It is of great Importance to take care to keep all Parts of the
Still clean, that there may be no Rust or Verdigrease in the Copper,
which will occasion Vomiting.

20. If it be necessary, the better to close the Joining of the
Still-head, it may be done with a Lute or Paste made of a Mixture of
powdered Chalk and Meal, wetted with Salt-water.

21. Now that several effectual Means are discovered, to make distilled
Sea-water wholsome, and also to distill it in much greater Quantity in
the same Still, in the same Time, and with nearly the same Quantity of
Fuel; it is reasonable to believe, that it will be of great Benefit to
Navigation, not only in saving much stowage room, for other important
Purposes; but also in procuring fresh sweet wholsome Water, instead of
stinking putrid Water, hitherto used; which must needs have a Tendency
to promote that putrid Distemper, the Scurvy. And if withal due Care
be taken, to exchange for fresh Air the putrid close confined Air of
Ships, which has occasioned the Death of Millions of Mankind; then
Navigation will become remarkably more healthy, and with little more
Danger to Health and Life, than at Land, except from Storms.

22. Now supposing, that in a sixty Gun Ship, the 110 Tuns of Water,
for four Months use, were distilled at the Expence of three Bushels of
Coals to a Tun, this would consume nine Chaldrons of Coals: And as a
Chaldron of Coals weighs about a Tun and half; hence it appears that
Coals will distill about eight times their Quantity of Water. And the
110 Tuns of Water weighing (at the Rate of 2240 Pounds to the Tun)
138 Tuns; and the nine Chaldrons of Coals weighing thirteen Tuns and
half, that is 94 Tuns and half less than the 110 Tuns of Store-water;
and allowing twenty-four Tuns and half for the Still, Water-casks, and
Coals, there will be 70 Tuns Weight of Stowage saved thereby for _other
Uses_. Or if some Tuns of Store-water are carried by way of Precaution,
which it will be advisable to do, especially at first, till they can
be assured, by repeated Experience, what Quantity can be depended upon
by Distillation; even then about half the Tunnage will be saved, which
will be a very material Advantage.

23. Tho’ when the distilling Liquor runs from the Bottom of the
Worm-pipe, thro’ a long Pipe fixed to it, the Waste by the ventilating
rushing Air, is not great when the Water in the Worm-tub is not hot;
yet the following Precaution, if needful, may be used, in distilling
by Ventilation, _viz._ to fix at the lower End of the Worm-pipe, by
means of a wooden Fawcet, a small Cask for a Receiver; the Fawcet to
enter the upper side of the head of the Cask, and in order to give a
free Passage for the great Quantity of ventilaing Air to pass off,
and withal at the same time to prevent the escaping of much moist
Vapour with it, it will be proper to fix at the Bung-hole a long
upright Pipe of Wood, or of any Metal. I used a Gun-barrel four Feet
and a half long; through which some small Degree of moist Vapour
escaped; as appeared by the Dampness of a Piece of Paper, fixed at a
little Distance above the Mouth of the Gun barrel. This Vapour became
visible, and much increased, when the Water in the Worm-tub was very
hot; at which Time, less is distilled into the Cask-receiver; then
also there is more Danger of the Spirit of Salt arising. And it was
observable, that the Water in the Worm-pipe Vessel heated much sooner
by Ventilation, than in the common Way of distilling. For which Reason
that Water ought to be changed so much the oftener, which can easily
be done at Sea. The Cocks also at the Side of the Worm-tub ought to be
large, in order to let the hot Water off the faster.

24. But tho’ the Water in the Worm-tub was sooner heated by
Ventilation, because a double Quantity of hot Steam passed thro’
it, more than passed thro’ it in equal Times in the common Way of
distilling; yet in the usual Way of Distillation the Liquor in the
Still is hotter, with equal Fire, as is evident by its aptness to boil
over thro’ the Worm-pipe; whereas in the ventilating Way it did not
boil over, notwithstanding a very hot Fire was purposely made for a
Trial. The continual Streams of ascending fresh Air, not only in some
Degree abating the Heat of the Water; but also incessantly carrying
off the more rarefied Particles of the Water, which, when expanded
into a repelling State, do thereby cause the overflowing Ebullition
of the Water. On which Account it is probable, that less Spirit of
Salt is formed and raised by Ventilation than without it. As also on
account of the fresh Air ascending, not from the Bottom of the Still,
where is the greatest Plenty of Salt, especially towards the latter End
of each Distillation; but about three Inches from the Bottom, _viz._
principally from the many Holes at the Surface of the Air-box.

25. And whereas the Quantity raised from the Still, and distilled into
the Cask-receiver, cannot be seen; the proper Quantity to be distilled
in each Distillation, may with great Accuracy be known, by having a
well closed Pewter Bottle of the Size of about half a Pint, with a
Brass Wyre as big as a Goose Quill fixed to it, the Wyre to pass thro’
the Receiver-cask, near the Bung-hole, which the floating Pewter Bottle
will raise up, till the Marks on the Wyre appear just above the Cask. I
made use of a Glass Viol for this Purpose. This Wyre will rise and fall
freely, notwithstanding the Motion of the Ship, if it passes not only
thro’ the Wood of the Cask, but also thro’ a metaline Pipe two or three
Inches long, fixed in that Hole. And it will be known by the simmering
or boiling Noise of the Water in the Still, whether it is hot enough to
distill; for the running of the Water into the Receiver-cask cannot be
seen.

26. As it might be suspected, that more Spirit of Salt would be
raised, and distilled over in the ventilating Way, than without it;
having procured 18 Gallons of Sea-water by the _Margate_ Hoy, which
was taken up at some Distance from the Shore, I put three Gallons of
this Sea-water, as soon as I had received it, into the Still; and when
it began to distill, Air was blown up thro’ it. For some Time, as is
usual, in the Distillation of Sea-water; no Spirit of Salt arose; but
after distilling some Time longer, there were very weak whitish Clouds,
with Drops of Solution of Silver in Aqua-fortis, as in the common Way
of distilling. Hence we see, that Ventilation does not increase the
Quantity of Salt, but rather probably somewhat decreases it, for the
Reasons above given, N^o 24.

27. I distilled three Gallons of Sea-water, which had stunk and became
sweet again; when about ten Quarts of it had been distilled off, then
there began to be very weak whitish Clouds with Solution of Silver, but
none with Solution of Mercury; which shows the Water to be hitherto
good, agreeably to what I formerly had found to be the good Effect of
distilling Sea-water, which had putrified, and become sweet again; of
which I published an Account in the Year 1739. But when I continued
the Distillation on, a quarter of an Hour longer, _viz._ till there
was but a Pint of Water remaining in the Still, and the Salts were
incrusted on its Sides, up near three Inches from the Bottom, and lay
in Heaps at the Bottom of the Still, then the distilled Liquor had
whitish Clouds in it, with the Solution of Mercury in Aqua-fortis. From
this Distillation we see, that Putrefaction, by dissolving the bittern
Salt and Bitumen, into very minute Parts, qualified them to combine
with the more fixed common Salt, so as to detain them from rising in
Distillation.

28. I distilled three Gallons of Sea-water, with the Proportion of six
Ounces of Mr. _Appleby_’s Lapis Infernalis, and six Ounces of calcined
Bones to 20 Gallons of Sea-water, as he directs. This Water lathered
well with Soap, and boiled Peas well.

29. I distilled also some Sea-water With half an Ounce of Stone Lime
to a Gallon, from the _Clee_ Hills in _Herefordshire_, which having
been preserved ten Months in a Firkin, had slacked to dry Powder.
This distilled Water did also lather well with Soap, and boiled Peas
well; which proves that the Lime, which is a fixed Body, does not
distill over with the Water. Since I made this Distillation, General
_Oglethorpe_ informed me, that his Father, Sir _Theophilus_, told him,
that Lime was one of the Ingredients, of what he and the rest of the
Patentees, in _Charles_ the Second’s time, called the Cement, with
which they made distilled Sea-water wholsome.

30. I distilled also some Sea-water with the like Proportion of
powdered Chalk, which boiled Peas well, and was better tasted than the
Waters distilled with Lapis Infernalis or Lime. I distilled also some
Sea-water with an Ounce of Chalk to a Gallon, but found no Difference
in the Taste of this, and that which had but half an Ounce of Chalk to
a Gallon: So that half an Ounce of Chalk to a Gallon of Water will be
sufficient; but where the Sea-water is salter, or more bituminous,
more Chalk may be added if needful.

31. Dr. _Alston_ of _Edinburgh_, in the Preface to the Second Edition
of his Dissertation on Quick-lime and Lime-water, says, that “the like
Effect was found in distilling Sea-water with Lime, that it neither
precipitated a Solution of Silver in Aqua-fortis, nor a Solution of
corrosive Sublimate in Water, nor did it form a Pellicle of various
Colours on its Surface, as did the Water distilled by Mr. _Appleby_’s
Process.” And I find, Page 35 of my Book on this Subject, that Lime of
Oyster-shells had the same good Effect, but required two Distillations;
I might then use too small a Quantity of that Lime. Hence it is
probable, that the Chalk, the Lime, the Lime in the Lapis Infernalis,
and the Lime in Dr. _Butler_’s Soap-lees, seize on and fix not only the
bittern Salt, but also the Bitumen of the Sea-water, as we learn from
the like Effect in the Purification of the Salt of Hartshorn. That the
saline Spirit arises chiefly from the bittern Salt, and not from the
more perfect Sea-salt, is probable from hence, _viz._ when I distilled
three Gallons of common Water, made as salt as Sea-water with common
Salt; no Spirit of Salt arose, even tho’ the Distillation was carried
so far as to leave the Salt, tho’ very damp, to lie in Heaps, and it
was incrusted on the Sides of the Still, for about three Inches from
the Bottom.

32. It is a considerable further Advantage, that Water thus distilled
by Ventilation, being thereby repleat and freshened with Air, has
for present Use a more agreeable Taste, than Water distilled without
Ventilation, which requires the standing a longer Time to have its more
disagreeable adust Taste go off. And as the volatile Oil of Pepper-mint
does rise on the Wings of the ventilating Air during the Distillation;
so also may that Part of the Bitumen, which is volatilized by Heat; as
also the volatile urinous Salts of the Sea-water, which arises from
animal Substances, be sublimed in the same Manner.

33. It was observable, that the Water distilled fast, even tho’ the
Water in the Still was below the Surface of the Tin Air-box, thro’
which the greatest Part of the ascending Shower of Air rushed. Hence
the ventilating Air, in ascending among the Vapours, carries them off
fast. Hence it is to be suspected, that this Method of Ventilation will
not do well for simple Waters, or fermented vinous Spirits; because
they being very volatile, much of them may be carried off in Waste.

34. It was observable, that in these Distillations of Sea-water, no
whitish Clouds appeared on dropping in Solution of corrosive Mercury,
not even when considerably more than four Parts in five of the Water
had been distilled over. And it was the same with the Mixture of Lapis
Infernalis, Lime, and Chalk; whence it is probable, that the Lime and
Chalk seize on and fix the more volatile bittern Salt, as does also the
Lime in the Lapis Infernalis. And it is well known, that Sugar, that
sweet Salt, cannot be made without Lime, on which, as its Centre of
Union, it fixes and granulates.

35. And whereas with a Solution of Silver in Aqua-fortis, which was
much weakened and diluted with Water, there appeared a faint Degree
of whitish Cloud, in all the above-mentioned Distillations, tho’ not
with the stronger Solution of Mercury till the Distillation was carried
on, much beyond four Parts in five of the Water in the Still; when
both Solutions caused remarkably white Clouds, especially the Solution
of Mercury; which indicates the Quantity of the Spirit of Salt which
was raised during the former part of the Distillation to be exceeding
small, since it could not seize on, nor disengage the Aqua-fortis from
the stronger Solution of Mercury, tho’ it did in a very small Degree
in the weak Solution of Silver, so as to let loose a very little of
the Silver, which thereby caused the faint Clouds. When a Drop of the
Solution of Mercury was dropped into the distilled Water, after a Drop
of the Solution of Silver, it resorbed the Silver Cloud, and made the
Water clear, by means of the great Proportion of acid Aqua-fortis that
was in it.

36. Now in order to make some Estimate of the very small Quantity of
Spirit of Salt in these several distilled Waters, I dropped a Drop of
the Solution of Silver into an Ounce, or 480 Grains of pure Rain Water,
which gave no Clouds; but on dropping in a Drop of Sea-water, which
weighed a Grain, the white Clouds were strong. And since Sea-water can
dissolve nine times more Salt than it has in it; therefore, supposing
the Drop to be so fully impregnated with Salt, then the Salt would
be the 480th Part of the Ounce of Water. But as there is nine times
less Salt, therefore the Proportion of the Quantity of Spirit of Salt
will be but the 4320th Part. And how much less must be the Proportion
of Salt in these distilled Waters, which is not sufficient to make a
sensible Impression on Solution of Mercury, and but a faint one on
much diluted Solution of Silver. Such distilled Sea-water will not
therefore, probably be unwholsome; almost all Spring-waters have some
Degree of Salt in them: But if there were more of the Spirit of Salt,
a very small Quantity of Pot-ash, or Pearl-ashes, or Salt of Tartar,
combined with it, will turn it into common Salt, the Quantity of which
would be extremely little.

37. It may be well to be provided in Ships with some Silver dissolved
in Aqua-fortis, mixed with pure Rain-water, or distilled fresh Water,
in the Proportion of sixty Drops to an Ounce of the Water; tho’ it is
probable, it may seldom be wanted, unless in some doubtful Cases, when
the Taste may not be accurate enough to perceive, whether there be any
Spirit of Salt in the distilled Water.

38. Since double the usual Quantity of Vapour may by Way of Ventilation
be carried off, common Salt may thus be made much sooner, cheaper, and
better; because as there is much less Fire used; so proportionably,
less of the fine acid Spirit of the Salt, in which its Virtue consists,
will be evaporated away: For it is well known, that the Salt is best
which has undergone the least Action of Fire in making.

39. This more speedy Method of evaporating will also be useful, in
making many other Evaporations; as in making Pot-ash, _&c._

40. But some are apprehensive, that this great Improvement in
Distilling, may be of ill Consequence in making those destructive
Spirits cheaper, which are already but too cheap. Had not the
Improvement been of great Benefit to Mankind in many other Respects,
I should have been far, very far, from endeavouring after it, or
discovering it. But should the Event be to make those Spirits cheaper,
and consequently, by spreading farther, more destructive, the
consequence of that will be, that the increased raging Devastation will
the sooner necessarily rouse the Nations to put a Stop to what must be
done hereafter; for if the Ravages continue increasing, as they have
done for sixty Years past, the human Species must needs not only be
greatly debased, but even in great measure diminished and destroyed.
And yet none of the Nations, whose very Vitals are thereby consuming
and destroying, endeavour to put any Stop to it, except the Heads
of the native Indians in _North-America_, who have long repeatedly
intreated the _English_ to sell them no Rum; which is as effectually
extirpating of them, as the Hornet did the unsubdued remainder of the
_Canaanites_.

41. If Mankind, instead of receiving and entertaining this Pest
with almost universal Applause and Approbation, could prevail with
themselves to be in earnest to use Means to deliver themselves from it;
then much might be done towards it, by lowering and weakening all kind
of fermented distilled Spirits with Water, to a salutary Degree, as is
now practised in our Plantations in _America_, in making Punch so weak,
as not to be hurtful; which, when it was much stronger, was well known
to destroy Multitudes. And where the like humane, wise, and laudable
Practice has been used in Ships, it has had the same happy salutary
Effect.

42. What Necessity or even Temptation can there be to be averse to
the making them wholsome, instead of being venomous and destructive?
and that not only of the Lives, but even of the Morals of Mankind.
How much therefore does it behove all, who have any Concern for the
Honour and Dignity of their own kindred Species, any Indignation at
its being thus debased and disgraced, any Bowels of Pity for the
vast Multitudes, not less than a Million, that are yearly destroyed
all over the World, by this moral as well as natural, and therefore
worst of all Evils that ever befel unhappy Man; to use their utmost
Endeavours to deliver Mankind from this Pest? But notwithstanding
this astonishing Ravage and Destruction of the human Species, yet the
unhappy unrelenting Nations of the World, seem as unconcerned about it,
as if only so many Thousands, nay, Millions of Caterpillers or Locusts
were destroyed thereby. Was there ever a more important Occasion to
rouse the Indignation of Mankind? Can we be calm and undisturbed, when
this mighty Destroyer rears up its invenomed Head every where? The
most zealous Advocates for Drams, even the unhappy besotted Dramists
themselves, the prolonging of whose Lives, and whose real Welfare both
here and hereafter, is hereby sincerely intended, cannot find fault
with this well-meant Remonstrance, in Defence of them, and of all
Mankind, against this mighty Destroyer, from one who has long been
labouring, and that not without Success, in finding Means to preserve
Multitudes of Lives, by various Ways.



_An Account of the great Benefit of_ Ventilators _in many Instances,
in preserving the_ Health _and_ Lives _of People, in Slave and other
Transport Ships_.


43. It is to be hoped that the several Means here proposed for having
fresh and sweet Water at Sea, will be of great Benefit in preserving
the Health and Lives of Multitudes of that valuable and useful Part
of Mankind, those who occupy their Business in great Waters; whose
Welfare I have long had at heart, and endeavoured to promote by various
Ways; especially by finding Means to procure them fresh salutary Air,
instead of the noxious, putrid, close confined pestilential Air, which
has destroyed Millions of Mankind in Ships. And it is to be hoped that
by diligent Researches, farther and farther useful Discoveries will
hereafter be made for the Benefit of Navigation.

44. The following, as they are strong Proofs of the great Benefit and
Usefulness of Ventilators in Ships, so they also fully prove that they
can most commodiously be fixed and worked in them, in contradiction
to the vulgar, false, and groundless Notion, that they take up too
much room, and are incommodious, and in a manner impracticable to be
worked, whereas the Men are eager to work them; and many more Persons
can be with Safety to their Health and Lives in a ventilated, than in
an unventilated Ship; which fully obviates the Objection as to the
Room they take up. In new and important Researches, the likeliest
Way to succeed, is to pursue a Thought not only by imperfect and
fallacious Reasonings, but when the Nature of the Thing requires it,
with a proper Series of Trials and Experiments. Thus in the present
Case, the principal Cause of the Sickness in Ships, is the noxious
putrid Air; the obvious Remedy is the exchanging that foul Air for
fresh, by effectual Means, which are seldom discovered by dwelling
only on Objections, but are usually the Reward of repeated diligent,
experimental Researches. Neither are we to be discouraged in these
our Pursuits by some Disappointments, for I have frequently found that
they lead to the Thing sought for: And by the like Clue of Reasoning
and Experimenting, there is the greatest Probability that we shall
succeed in another very important Research, _viz._ the preserving
much longer from Decay the Timbers of Ships laid up in ordinary in
Harbour: For as we are assured by daily Experience, that the Decay is
wholly owing to damp, close confined putrid corroding Air; so the only
Remedy for this Evil, is the frequently changing the Air among the
Timbers, by plentiful Ventilations; which we find by happy Experience,
can be effected to such a Degree, as give reasonable Hopes, enough to
encourage our farther Trials and Researches.

45. Captain _Thomson_ of the _Success Frigate_, in his Letter to me
dated _London, Sept. 25, 1749_, says, “That during the Ventilation,
the Lower-deck Hatches were commonly kept close shut; by which means
the Air was drawn down into the Hold, from between Decks, thro’ the
Seams of the Ceiling, along the Timbers of the Ship; by which means
we found the foul Air soon drawn off from between Decks. Our Rule
for ventilating was for half an Hour every four Hours; but when the
Ventilating was sometimes neglected for eight Hours together, then we
could perceive, especially in hot Weather, a very sensible Difference
by that short Neglect of it; for it would then take a longer Time to
draw off the foul Air. Our general Rule was, to work the Ventilators
till we found the Air from them sweet. We all agreed that they were of
great Service; the Men being so sensible of the Benefit of them, that
they required _no driving_ to work that which they received so much
Benefit by. We found this good Effect from Ventilation, that tho’ there
were near 200 Men on board, for almost a Year, yet I landed them all
well in _Georgia_, notwithstanding they were pressed Men, and delivered
me out of Goals, with Distempers upon them. This is what I believe but
few Transports, or any other Ships, can brag of; nor did I ever meet
the like Good-luck before; which, next to Providence, I impute to the
Benefit received by the Ventilators. It is to be remarked, that we who
lay wind-bound, for four Months, with our Expedition Fleet, which soon
after invaded _France_, were very healthy all the time, when they were
very sickly in all the Ships of that Expedition.

46. “This certainly occasioned all kind of Grain Provisions to keep
better and longer from Weevels, than otherwise they would have done;
and other Kinds of Provisions received Benefit from the Coolness and
Freshness in the Air of the Ship, which was caused by Ventilation.”

47. Mr. _Cramond_ also informs me, that he found the good Effect of
Ventilators on board a Slave-Ship of his with 392 Slaves, twelve of
which were taken on board, just before they sailed from _Guinea_,
ill of a Flux, which twelve all died; but the rest, with all the
_Europeans_ in the Ship, arrived well at _Buenos Ayres_.


 _The following is a Letter to me from Captain_ ELLIS, viz.

  “Sir,

48. “Could any thing increase the Pleasure I have in a literary
Intercourse with you, it would be to find that it answered your End
in promoting the public Good. The _Vis-inertiæ_ of Mankind is not the
only Difficulty you have had to encounter, but their Ignorance and
Prejudices, which are almost insuperable. It is to your Perseverance
and Resolution, that the little Progress you have made is due: Indeed
I ought not to say little; for it is a great Step to have found the
few that have Hearts good enough to relish your Plan, and Heads
sufficiently clear to discern the most effectual Method of advancing
it. It does Honour to those noble and other worthy Personages that
join you in Acts of such extensive Humanity, as the Introduction
of Ventilators to Hospitals, Prisons, Ships of War and Transport,
_&c._ as they must necessarily render the Miseries of the first more
supportable, and the close and constant Confinement of the others less
prejudicial and fatal to their Health and Life. It is to be lamented
that they are not more generally made use of; for, notwithstanding
their Advantage is apparent and incontestable, it is scarce credible
how few are to be found among the vast Number of Ships daily employed
in carrying Passengers, Slaves, Cattle, and other perishable
Commodities. Those of your Invention, which I had, were of singular
Service to us; they kept the Inside of the Ship cool, sweet, dry, and
healthy: The Number of Slaves I buried was only six, and not one white
Man of our Crew, (which was thirty-four) during a Voyage of 15 Months;
an Instance very uncommon. The 340 Negroes were very sensible of the
Benefits of a constant Ventilation, and were always displeased when it
was omitted: Even the Exercise had Advantages not to be despised among
People so much confined. I must not, however, forget that Ventilation
alone is insufficient to keep Disorders out of Ships; for often
Infections are brought aboard by the Slaves, or others; and frequently
Diseases are produced by feeding on bad or decayed Food, but oftener
still by Insobriety; for I have ever remarked that the immoderate Use
of spirituous Liquors in warm Climates, is more pernicious and fatal
even than the Malignancy of the Air itself. In cold Countries too,
where I have had Experience, those Sailors, or others, who accustomed
themselves to hard drinking, especially of Drams, had the Scurvy
in a terrible Degree; whereas those who were temperate or sober,
either escaped it entirely, or had it but moderately. The Effects of
Drunkenness was still more discernable among the Indians adjoining our
Settlements in _Hudson’s-Bay_, who are a feeble, diminutive, chilly,
indolent Set of People. On the contrary, those who come from the inland
Parts (who are unused to drink Brandy) are brave, active, robust, and
industrious. The same Difference is observable in the _Africans_, and
perhaps among the Inhabitants of most other Nations, did we attend to
it. It was to the unusual Sobriety of my Crew, that I ascribed, in
some measure, their uncommon Healthiness; for Sailors breathe a purer
Air, and enjoy more Exercise and Liberty, than Passengers or Slaves;
wherefore their Ailments are owing to bad or disorderly Living, as well
as to unwholsome Air.

“Could I but see the immoderate Use of spirituous Liquors less general,
and the Benefits of Ventilators more known and experienced, I might
then hope to see Mankind better and happier. I am,

                                          “SIR,
                                          “_Your most obediens Servant_,
                                          HENRY ELLIS.”

  Bristol, Dec.
  26, 1753.

49. And, by the like good Conduct, in his next Voyage in the Year 1755,
not one of 312 Slaves died; and all his 36 Sailors arrived alive and
well at _Bristol_.

50. And the Earl of _Halifax_ has often informed me of the great
Benefit they found by the Use of Ventilators, in several _Nova
Scotia_ Transport-Ships, twelve to one more have been found to die in
unventilated than in ventilated Ships. It is indeed a self-evident
Thing, that the changing the foul Air frequently in Ships, in which
there are many Persons, will be a means of keeping them in better
Health than not doing it; which makes it the more astonishing that
effectual Proposals to remedy so great an Evil, should be received
with so much Coldness and Indifference by Mankind. They little
consider that it is the high Degree of Putrefaction (that most subtile
Dissolvent in Nature) which a foul Air acquires in long stagnating,
which gives it that pestilential Quality, which causes what is called
the Goal-Distemper. And a very small Quantity, or even Vapour of this
highly attenuated Venom, like the Infection or Inoculation for the
Small-pox, soon spreads its deadly Infection. Ought not Men therefore,
from the common natural Principle of Self-Preservation, to use their
utmost Endeavours to shun this pestilent Destroyer, by which Millions
of Mankind have perished in Ships?



_An Account of some Tryals to cure the ill Taste of_ Milk, _which is
occasioned by the Food of_ Cows, _either from Turnips, Cabbages, or
autumnal Leaves_, &c. _Also to sweeten_ Stinking-water, &c.


51. This Method of blowing Showers of Air up thro’ Liquors, will be of
considerable Use in several other Respects, as well as in Distillation,
as appears by the following Trials, _viz._

52. I have been informed that it is a common Practice, to cure the ill
Taste of Cream from the Food of Cows, by setting it in broad Pans over
hot Embers or Charcoal, and continually stirring it, till scalding hot,
and till cool again: But when I attempted to do this much sooner, and
more effectually, by blowing Showers of Air up thro’ it; I soon found
it to be impracticable, by reason of its very great Degree of frothing
up. The ill Taste must therefore be got out of the Milk, before it is
set for Cream; which I have been told, has been practiced, and that
with some benefit, by giving the Milk a scalding Heat, without stirring
it.

53. _May 22._ I ventilated some ill tasted, new unheated Milk of a
Cow which was purposely fed with Crow-Garlick mixed with cut Grass.
After 15 Minutes Ventilation the Taste was a little mended; in half
an Hour’s blowing it was something better. At the Hour’s end it had
the same Taste, but was sensibly better than the unventilated Milk. I
was disappointed of an Opportunity to repeat the Experiment with Crow
Garlick Milk, with a scalding Heat; it would then probably have been
soon perfectly cured; as it is reasonable to believe from the Event of
the following Experiments, _viz._

54. _August 23_, four Quarts of ill tasted new Milk, from a Cow which
had fed eighty-four Hours on Cabbage Leaves only, and drank during that
Time very little Water; were put into a leaden Vessel, eight Inches in
Diameter, and thirty Inches ches deep. The leaden Vessel was heated in
a large Boiler, and set into a Vessel of hot Water; thereby to give the
Milk a scalding Heat, and also keep it hot. In ten Minutes Ventilation
it was perfectly cured of its ill Taste; and after standing twenty-four
Hours in a broad Pan, there was a thick Scum which was half Cream and
half Butter, free from any ill Taste; the skimmed Milk was not sheer or
thin: So here is a Method to make good Butter from ill tasted Milk.

55. The Froth of the Milk was so great, by reason of a too brisk
Ventilation, as to make it froth over the Vessel, which was thirty
Inches deep; if it had not been kept down, by constantly lading and
breaking the very large Bubbles of Froth. But when the Ventilation is
more gentle, the Froth has risen but three Inches from six Quarts of
Milk, which was nine Inches deep. The Cabbage Milk was but six Inches
deep. I repeated the like Operation the same Day, with the Evening
Milk of the same Cow; but giving it only a Heat, that I could bear
my Fingers in, for a little Time; with this Degree of Heat, after
forty-five Minutes Ventilation, the Milk (tho’ much better tasted) yet
was not so compleatly cured, as the former Milk. Hence we see, how
necessary Heat is, to volatilize the rancid Oyl (which gives the ill
Taste) to such a Degree as to cause it to fly off by Ventilation.

56. It was observed that what was milked from this Cow a Week after she
had done eating the Cabbage, had an ill Taste.

57. I have not as yet had an Opportunity, to try to cure, in the same
Manner, the ill Taste of Milk, which is occasioned by Cows feeding on
autumnal Leaves, or Turnips, they having probably eaten this Autumn,
the fewer Leaves, on account of the Plenty of Grass, occasioned by much
Rain; which has also hitherto prevented Turnips from being rancid,
which are observed to be most so, when they shoot out in the Spring. As
Opportunities offer I purpose to make Trials, which I conclude others
will also do, which will probably be attended with the same good
Effects as that on the Cabbage Milk.

58. But tho’ the ill Taste of Milk from feeding on Cabbage Leaves, was
thus effectually cured by volatilizing with Heat, and dissipating by
Ventilation the rancid Oil; yet the bitter Taste of a strong Infusion
of Chamomel Flowers in six Quarts of Water, was not sensibly abated by
an Hour’s Ventilation of it, while scalding hot.

59. I am informed that, in _Devonshire_, they set the Pans of Milk
on Trivets, making Fires under them, to give the Milk, gently and
gradually a scalding, but not a boiling Heat, which would disturb the
rising Cream; and then set it on the Floor in the Milk-house to cool,
where in twelve Hours it has a thick Scum, partly Butter and partly
Cream: The skimmed Milk is very thin and sheer; and the Cream in great
Plenty and delicious, except it gets a smoky Taste, which it is apt
to do; and which might probably be prevented, by having a Range of as
many Stoves, as there are Pans of Milk to be used at one Time; all to
be warmed by one Fire, either at one end, or the middle of the Flue or
Funnel in the Brick-work, which conveys the Smoke and Heat under the
Stoves. And as the Pans nearest to the Fire will soonest have their due
Heat, on their Removal to bring the farthest and coolest Pans nearest
the Fire; and instantly covering the uncovered Stoves with proper
Covers to prevent the Heat and Smoke from coming out; by this Means the
Milk would all be soon heated, with any kind of Fuel, and that with
much less in Quantity than in the common Way.

60. And the more effectually to prevent the Smoke from coming at the
Milk, it may be well to have the broad outer Rim of the Pans turned
perpendicularly downwards, three or four Inches, that it may enter deep
into a circular Groove of Sand; and if it shall be needful the Sand
may be wetted in order the more effectually to prevent the Passage of
the Smoke: I thought of this Method about fifty Years since on tasting
the smoky Butter in _Somersetshire_. By the same Means the Poor might
save much Fuel in boiling the Pot, especially in Summer, when a Fire is
wanted only for boiling the Pot.

61. When any Pans are to be removed from the Stoves, the Ascent of the
Smoke thro’ the uncovered Stove, may be prevented by first closing the
Flue near the Fire, by an Iron Sliding-shutter or Register.

62. Milk might thus most commodiously be heated to a scalding Heat with
little Fuel, fit for Ventilation, in a Vessel of a proper Depth, set
in the same Manner as the Pans in a Stove, to secure it from Smoke,
with Bellows fixed properly near it: (see _Fig. 3_.) By this Means
there would be little Trouble or Expence in curing ill tasted Milk by
Ventilation.

63. _May_ 14th, meerly to see what the Event would be, a Gallon of new
Milk, just from the Cow was ventilated, for an Hour and half, which
produced six Ounces of Butter; and tho’ it was ventilated half an Hour
longer, yet no more Butter was made; it was whitish, wanting both the
Colour and Taste of good fresh Butter.

64. I am credibly informed, that in the Places famous for making the
best fresh Winter Butter, they set the Pot of Cream in warm Water, so
long as till it has acquired that small Degree of Sourness, which it
very soon has in warm Summer Weather, which gives it its agreeable
Flavour. And in order to give it Colour, they grate a well coloured
Carrot into a little Milk, which as soon as stained, is strained from
the Carrot thro’ a Sive, and then mixed with the Cream.

65. It is found by Experience, that the Quantity of Cream is increased,
by putting into the Milk a little warm Water in Winter, and cold in
Summer; which being thereby, in some Degree thinned, the Cream is
thereby more easily disintangled, so as more freely to ascend to the
Surface of the Milk.

66. I ventilated three Gallons of stinking _Jessops-well_ purging
Water. On first blowing, the Smell of the ascending Vapour was very
offensive, which Offensiveness abated much in five Minutes: In eleven
Minutes the Smell was much better: In twenty Minutes the Water seemed
sweet both in Smell and Taste; and not sweeter at the End of forty-five
Minutes, fifteen or twenty Minutes will probably suffice.

67. _July_ 20th three Gallons of stinking Sea-water were ventilated; in
five Minutes it was much sweetened, and no ill Smell in the ascending
Air, tho’ at first it was very offensive: At the End of ten Minutes it
had a small Degree of ill Taste; after twenty Minutes no ill Taste or
Smell. It frothed near a Foot high during Part of the Ventilation; this
from the Bitumen, _&c._

68. Some Sea-water which was made to stink with Flesh and Isinglass
being put into it, was not made perfectly sweet, not even by a
ventilated Distillation, and an Hour’s more Ventilation after it was
distilled; so that Putrefaction with animal Substances, is not easily
compleatly cured by Ventilation.

69. When the Water was 27 Inches deep in the leaden Vessel, no Air
could be blown up thro’ it by the Force of the Bellows. But at 18
Inches Depth, the Air could freely be blown up in Showers thro’ the
Water; when therefore it is requisite to blow up thro’ great Depths of
Water, the Bellows may be worked with a Lever, as Smiths Bellows are
worked.

70. As it is found by Experience, that the Milk and Butter of Cows,
which drink stinking Water, has a very bad Taste, this plainly shows
that the Water retains its putrid Quality when mixed with the Blood;
whence it is much to be suspected, that the stinking Water which is
drank in Ships, by retaining its putrid Quality, even when mixed with
the Blood, may thereby promote that putrid Distemper the Scurvy, as
well as some other Distempers. And much more does the putrid close Air
in Ships, which is mixed with the Blood from the Lungs, promote putrid
and other Disorders: By the same Means also, pestilential Infections
are taken in: For as the salutary Properties of good Air, are conveyed
to the Blood by the Lungs, so are also the malignant Qualities of bad
Air.

71. Thus also the putrid Water in marshy aguish Countries, may be a
Cause of Agues, as well as the putrid Air which they breathe; which, as
well as the putrid Water, may probably carry some of its putrid Quality
into the Blood thro’ the Lungs. This Method therefore of sweetening
stinking Water, by blowing Showers of Air up thro’ the stinking Water
of some aguish Places, may be beneficial.

72. Live Fish may well be carried several Miles, by blowing now and
then fresh Air up thro’ the Water, without the Trouble of changing the
Water; for this Ventilation will not only keep the Water sweet, but
also enrich it with Air, which is necessary for the Life of Fishes;
with which Air they supply their Blood, by breathing the Water, thin
spread, between their Gills: But stinking Water will kill Fish.

73. I have found that much of the heating Oil may be got out of
Tar-water, by blowing Showers of Air up thro’ it when scalding-hot, for
15 or 30 Minutes, the longer the better; the less volatile, and more
salutary Acid remaining.


[Illustration:
  _page 59_
 _Fig. 1._
 _Fig. 2._
 _Fig. 3._
 _T. Jefferys sculp_
]



AN APPENDIX TO THE

Treatise _on distilling_ Sea-Water, _sweetning_ Milk, _&c. which gives
a farther Account how to procure still greater Plenty of_ Fresh-water
_at Sea, and to sweeten ill-tasted Milk, Stinking-water, and musty
Liquors_, &c. _by blowing Showers of Air up thro’ them_.


74. Several considerable Improvements having been made on the Subjects
of this little Book, since the Publication of it, I shall here give
a short Account of them, hoping they may in several Respects be of
Benefit to the World; especially the great Improvement in distilling
Plenty of Fresh-water at Sea.

75. In order to bring the Method of procuring Plenty of good
Fresh-water at Sea, into practice, several previous Trials were made,
at the laudable Motion and Desire of _Peter Wyche_, Esq; in a Still
containing 24 Gallons of Water, at Messrs. _Steel_ and _Stephens_’s
Copper Workhouse, near the _Falkon-Stairs, Southwark_. The first thing
to be done, was to find out the proper Size of the Diameter of the
Copper Air-box. The Diameter of the Still, near its Bottom, being 19
Inches, the Diameter of the first Air-box was 18 + ½ Inches. On
three several Trials, a _Winchester_ Quart of Water was distilled in
five Minutes by the common way of Distillation; and by Ventilation
a Quart was, in 3 or 4 Trials, distilled in 2 Minutes; but at the
Distillation of the ninth Quart, the Water was so much cooled by the
ventilating Showers of ascending Air, as to require 5 Minutes and 44
Seconds. Now this great Decrease of the Quantities distilled, was
plainly owing to the too great Breadth of the Air-box, which hindered
the Fire from heating and keeping hot the Water which was above it, to
such a Degree, as to have no Distillation in the common way, for 8 or
10 Minutes after the Ventilations; for the half Inch Circle of Water
which was not covered by the Air-box, was but one nineteenth Part of
the whole. The next Trial, in the same Still, was made with an Air-box,
whose Diameter was 13 Inches, its Area therefore 127 square Inches;
which deducted from 271 square Inches, the whole Area or Breadth of
that part of the Still, there remains 144 square Inches, for the Area
of the three Inch broad annular Circle round the Air-box, _viz._ 17
square Inches more than the Area of the Air-box. The Event was, that
in seven Distillations in the common way, a Quart was distilled in 5
Minutes, sometimes in a little less, and sometimes in a longer Time.
And by Ventilation 14 different Quarts were distilled in different
Lengths of Time, from a Quart in 2 Minutes and 6 Seconds, to 3 or 4
Minutes.

76. I then repeated the like Trials with my small three Gallon Still,
distilling in the common way a Pint in 10 + ½ and 9 Minutes; and
seven separate Pints were distilled by Ventilation in 3 + ½ to 4 + ½
Minutes. Hence we see that Ventilation has a more steddy and constant
good Effect where the Air-box is less in Proportion to the Still, than
it was in the other two Distillations: For in this lesser Still, only
27 out of 99 square Inches were ventilated, 72 square Inches being
unventilated. It will therefore probably be advisable to have the
Air-boxes of other Stills to be nearly in the like Proportion to the
respective Stills, the Diameter of this Still being 11 + ½ Inches, of
its Air-box 6 Inches.

77. As by repeated Trials a Quart of Water was distilled in the common
way in five Minutes, in the above-mentioned twenty Gallon Still, so an
120, or two Tuns and 14 Gallons, may be distilled by Ventilation in
twenty Hours.

78. Mr. _Wyche_, who was present at the Trials near the
_Falcon-Stairs_, observing the Water in the upper Part of the Worm-tub
to be reeking hot, tho’ the Water below it was cool, very rightly
proposed to have the hot Water run from the upper part of the Worm-tub,
thro’ a small Copper Pipe, into the upper Part of the Still, as fast as
it was distilled off, the running Quantity of Water to be adjusted by
a Turn-cock in the Pipe. This I tried in my little Still, by conveying
the upper warm Water of the Worm-tub into the Still thro’ a small Pipe
Which passed thro’ a Hole in the Head of the Still, almost down to
the Bottom of the Water in the Still: My Reasons for doing of which
were, _viz._ lest the less hot Water, by running on the Surface of
the boiling Water, might considerably check the Ascent of the rising
Vapours; whereas, being mixed and blended with the lower Water, it
will soon acquire a due Heat. Another Reason why I chose to lead the
entering Rill of Water so slow, was, that it might be intimately mixed
with the Chalk, which is there in an agitated State by reason of the
Action of the Fire. The Event was as follows, _viz._ that six separate
Pints of Water were distilled by Ventilation during the running in of
the warm Water, some in 3½ Minutes, others in 4 Minutes, 4 + ½, and 4
Minutes, 50 Seconds, which was the case of the second Pint.

79. Hence we see the great Benefit of this ingenious Improvement of
Mr. _Wyche_’s in distilling Sea-water, where the Still will be filled
with the same Liquor as the Worm-tub; but this Method cannot so well
be put in Practice in other Distillations. The Benefit of thus gently
and incessantly keeping the Still full, will save about one-fourth of
the Time and Fuel, which it would otherwise require to refill with cold
Liquor, and bring to a distilling Heat. This great Advantage, added to
that of distilling about double the Quantity by Ventilation, must needs
both together be of so great Improvement in distilling three Parts in
four more than usual, as will be of the greatest Benefit to Navigation
in several respects. By this means the Still need be emptied and
cleansed from the Chalk, and very salt Water, only at the end of each
daily Distillation.

80. And whereas if all the Chalk requisite for a whole Day’s
Distillation were put into the Still at once, it might be suspected
that such a Quantity laying at the Bottom of the Still, might hinder
the boiling of the Water: I put into a broadly flat-bottomed sauce-pan,
half an Inch Depth of powdered Chalk, and two Quarts of Water boiled
in ten Minutes: The Water mingling freely, especially in the time of
boiling, among the thin pappy Chalk, was freely acted on by the Fire.
But as in boiling it frothed much, it may be proper to put at first
into the Still only as many half Ounces of Chalk as there are Gallons
of Water; and afterwards from time to time in proportion to what
additional Water shall have run into the Still, at a Hole purposely
made in the Head of the Still, taking care to ventilate while the
Chalk is putting in, which will cause it to mix intimately with the
Water, and thereby have the better Effect on it. And perhaps a less
Proportion of Chalk than half an Ounce to a Gallon of Sea-water may
suffice.

81. The Degree of Fulness or Emptiness of the Still, may be known by
putting a small floating metalline Vessel, in at the Chalk Hole, with a
long slender Wire to it.

82. Mr. _Wyche_ thought of other Means the better to promote
Distillation, _viz._ by conveying the Air from the Bellows through a
Pipe with several spiral Coiles, thereby in passing thro’ boiling Water
in the Still, to make the ascending Showers of the Air the hotter,
and so the less refrigerating. Also to have the warm Water pass from
the Worm-tub, in a Pipe, with several the like spiral Coiles, in the
Head of the Still; thereby the more to heat the entering Water. But we
find, by the above-mentioned Experiments, that there is no occasion for
either of them; but if wanted may be used.

83. As to the Benefit of Ventilators in preserving the _Health and
Lives_ of People in Slave and other Transport Ships, I have received
farther Confirmation of their great Benefit, in a Letter from Dr.
_Demainbray_, who has shewn Courses of Experimental Philosophy to
his Royal Highness the _Prince_ of _Wales_ and _Prince Edward_, viz.
“That in the Year 1753 Ventilators were put into the Vessels in the
Slave Trade at _Bordeaux_, and in other Ports of _France_; the happy
Effect of which was, that instead of the Loss of one-fourth of those
valuable Cargoes, in long Passages from _Africa_ to the _French_
Plantations, the Loss seldom exceeded a twentieth. And since my Return
to _England_, I have been informed of a _French_ Vessel, which by this
self-evidently reasonable Precaution, saved 308 out of 312 Slaves,
spite of most tedious Calms and a long Passage.” And Dr. _Garden_,
in his Letter to me, dated _Charles-Town, South-Carolina, March_
24th, 1756, says, _viz._ “It is indeed very wonderful, that the Slave
Merchants do not come into the Use of Ventilators. There are few Ships
come here from _Africa_, (even though they call for fresh Provisions
and Water at the _Islands_) but have had many of their Cargoe thrown
overboard; some one-fourth, some one-third, some lose half; and I have
seen some that have lost two-thirds of their Slaves. I have often
gone to visit these Vessels on their first Arrival, in order to make
a Report of their State of Health to the Governor and Council; but
I never yet was on board one, that did not smell most offensive and
noisome. What from Filth, putrid Air, putrid Dysenteries (which is
their common Disorder) it is a wonder any escape with Life.”

84. A probable Means lately occurred to my Thoughts, tho’ not perfectly
to cure, yet much to abate the great Degrees of stinking of the
Bilge-water in the Well of Ships, _viz._ by laying at the Bottom of
the Bilge-water, round the Main-mast, Copper Pipes full of very small
Holes, not one twentieth of an Inch in Diameter; and blowing Showers
of Air up thro’ them from small Black-smith’s Bellows, fixed out of
the way, within the Well. Such Bellows may be worked with great Ease,
for one, two, or three quarters of an Hour, in every 24 Hours, more
or less, as shall be found requisite by Experience: But with this
Precaution, that whenever the Water stinks much, first to pump it out
of the Ship, and after letting in sweet Water, then to ventilate it
a little now and then, as shall be found needful; but care must be
taken not to ventilate very stinking Water, because it may increase
the Unwholsomeness of the foul Air in Ships. By this means Ships will
probably be made something less unhealthy; for the putrid Vapours which
arise from stinking Water, must needs greatly contribute to increase
the Putridness, and consequently the Noxiousness of the foul Air in
Ships. This Precaution therefore, with Ventilators frequently to convey
off the close foul Air, will be effectual Means to make Ships much
more healthy; as will the changing the foul Air in Goals, Hospitals,
and sick Rooms, with proper Precautions, make them more wholsome: And
it is with pleasure that I observe, that these salutary Means are
coming more in use in Hospitals, _&c._ either by means of Ventilators,
or by admitting fresh Air in small Quantities, and those spread in
thin Sheets, so as not to have the entering Air blow directly on, and
incommode the Patients. Where it can be had, a thorough Air entering on
one side, and passing out on the other side of Wards or Rooms, will be
best; because the Change will be almost constant, and may be as gradual
and gentle as we please. I shall give a more particular Account of this
in my second Volume of Ventilators.

85. As to the curing the ill Taste of Milk from the Food of Cows; and
also curing musty Liquors, I made the following Trials, _viz._ When in
the Beginning of _March_ the Turnips had made large Shoots, and were
thereby become very rancid, two Cows being fed with Turnips only for
seven Days, their Milk had a very disagreeable Smell and Taste. On
ventilating it scalding hot, with ascending Showers of Air, at first
the ill Smell increased, but in two Minutes that Smell was much abated;
and with five Minutes Ventilation, there was only the common Smell
of good Milk; which shows that the rancid Oil of Turnips, which gives
the ill Taste, is very volatile: After ten Minutes Ventilation, there
was no ill Taste or Smell; and it was the same after 15 and 30 Minutes
Ventilation. By this means therefore the ill Taste of Milk from some
Food of Cows, may easily be cured. Experience will show what Degrees of
Ventilation will be requisite for larger Quantities of Milk; as also
for curing the ill Tastes from different Kinds of Food; as also from
the shorter and longer Times of feeding on such Foods. It is observable
that the Breath of these Cows was disagreeable; whence we see how
freely contagious Infections may be conveyed through the Lungs, from
tainted putrescent Blood.

86. A Cow having been fed for sixty Hours with a good Quantity of Crow
Garlick, mixed with cut Grass, towards the end of _June_, the Milk
had a very disagreeable Smell and Taste; which was not cured, though
something better, after 30 Minutes Ventilation, while scalding hot. I
repeated the same Ventilations for 15 Minutes, with the two following
Evening and Morning Milks of the same Cow, _viz._ 12 and 24 Hours after
the Cow had left off eating _Crow-Garlick_; at which times the ill
Taste and Smell was sensibly abated before Ventilation, and something
more after it, yet was far from being cured. Hence we see that the ill
Taste and Smell of the _Crow-Garlick_ Milk, cannot thus be cured, tho’
somewhat amended. The ill Taste of this Cow’s Milk continued for about
five Days after she had left off eating of the _Crow-Garlick_. And
perhaps where Cows have eaten but a small Quantity of it, the Abatement
of the ill Taste may be so considerable, as to recompence the Trouble
of ventilating it. As Opportunities offer, I will make the like Trials,
with other ill-tasted Milks, such as that from autumnal Leaves, _&c._
and hope that others will do the like.

87. Cream or Milk Sillabubs may most commodiously and easily be made in
Plenty, in a few Minutes, by means of a small Tin Air-box, three Inches
in diameter, and three quarters of an Inch deep; the flat Bottom of the
Pot, which contains the Cream or Milk, to be but little wider than the
Air-box, that the Air from the Box may the better come at it: But the
wider and deeper the upper Part of the Pot is, so much the better, for
the Froth expands much.

88. Scalding-hot musty Vinegar was cured by repeated Trials, of near
three Gallons in each Trial, by ten Minutes Ventilation. And giving
Vinegar a scalding Heat, does not weaken or damage it, as it does Wine,
whose vinous Spirit is carried off both by Heat and Ventilation; for
when some strong musty Raisin Wine was ventilated hot, it was cured
in five Minutes: But the vinous Spirit, which strongly affected the
Nose in flying off during Ventilation, being gone off, the vapid Wine
would not kindle into a Blaze, when thrown into the Fire, as it did
to a great Degree before it was heated and ventilated. Neither musty
Wine nor Vinegar were cured, tho’ something bettered by 30 Minutes
Ventilation, when cold.

89. Mr. _Jones_, a Chemist in _Cranbourn-Ally, Leicester-Square_,
ventilated a Gallon of Proof Malt Spirits 15 Minutes cold, in which
time it wasted two Ounces and half; whereas a like Quantity of common
cold Water wasted but half an Ounce in 15 Minutes Ventilation, _viz._
but one-fifth part of what the Spirits did; and the same Spirits
ventilated hot, wasted no less than 5 Ounces in 5 Minutes; which
Ventilation made them sensibly better tasted than the unventilated. But
the great Waste shows that these volatile vinous Spirits, ought not to
be ventilated, neither hot nor cold. Besides that, the 15 Minutes cold
Ventilation had but little Effect in bettering the Spirit.

90. In order to know whether Fish in a Vessel of Water would live
the longer for having Showers of Air blown up thro’ the Water, _May
25, 1756_, at seven in the Morning, the Wind N. E. the Mercury in
_Farenheit_’s Thermometer, 50 Degrees, and it continued so cold, that
at one o’clock it rose but to 60 Degrees; I put twelve Dace into a Pail
_A_ in two Gallons of fresh Pond-Water, thro’ which a Stream ran, and
twelve more into a Pail _B_, with the like Quantity of Water; one of
which Fishes in _B_ was sick, as appeared by turning its Belly upwards;
as were also two Fishes in the Pail _A_, which was occasioned by being
all brought in a Pail above half a Mile from the _Thames_.

91. At 45 Minutes past 8, most of the Fish in the Pail _B_, were turned
Belly upwards, and lay as dead; at 30 Minutes past 9 seven of them were
dead; at 30 Minutes past 11 all but three were dead; at two o’clock but
two Fish remain alive in _B_; which remained alive, tho’ sick, at ten
that Night, _viz._ at the end of 14 Hours.

92. The good Effect of blowing every quarter of an Hour, with 25
Strokes each time with double Bellows, Showers of fresh Air up thro’
the Water, was, _viz._ they all continued well, and the larger of the
two sick Fish recovered; but the lesser died at 4 o’clock, _viz._
at the end of nine Hours; upon each Ventilation it turned its
Back upwards; but soon after the Ventilations, it constantly fell
precipitate with its Head foremost, to the Bottom, and there turned
Belly upwards. After 4 o’clock the ventilated Water frothed with larger
Bubbles, this owing to the Slime of the Fish. The last Ventilation
was at 10 at Night, when the Fish in the ventilated Water were well,
and would probably have long continued so by the Salutariness of
Ventilation; but that being discontinued, they were all found dead the
next Morning, except one which had some small Degree of Life.

93. _June 7_, the Wind S. W. cloudy, the Thermometer at 58 Degrees,
13 live Gudgeons were put into two Gallons of fresh Pond-water in a
Pail _A_; and a like Number into a Pail _B_, at 10 Minutes before 7
in the Morning. At 50 Minutes past 7, two in _B_ began to be sick; at
8, half of them came up for Air, and showed Uneasiness; at 15 Minutes
past 8 two are dead; at 30 Minutes past 8, eight more turned Belly
upwards; at 8 Minutes past 9, five are dead in _B_, and five more sick;
at 30 Minutes past 9, seven are dead, and four sick, two well; and 30
Minutes past 10, eight are dead; at 11 two only alive, and also well,
though they showed some Uneasiness by their raising their Mouth to the
Surface, which they continued to do till nine, when they were taken out
of the Water. Hence we see, by this, and the preceding Experiment on
Dace, that one or two Fish may be kept alive many Hours longer than a
greater Number can be, by means of the small Portion of fresh Air, that
is continually mixing with the Water, on which it presses.

94. The Water in the Pail _A_ was ventilated from 10 Minutes before
7, to 6 in the Evening, by blowing every quarter of an Hour Showers
of fresh Air up thro’ it, with 25 Strokes of the Bellows; by which
means the Fish continued all well, laying quiet at the Bottom: At six
we ceased to ventilate; for an Hour and half after which, there was
no Signs of Sickness, after two Hours two of them showed Signs of
Uneasiness; and at nine most of the Fishes turned Belly upwards, and
lay at the Bottom dead or dying. By comparing this Event with that at
eight in the Morning, we see there is more Air in this ventilated Water
than in the Pond-water, as is probable by the Gudgeons living longer
in it without Ventilation, than in the Pond-water. And accordingly the
specific Gravity of unventilated Pump Well-water, was a very small
Matter greater, than that of the same, after being ventilated with 100
Strokes of the Bellows, as I found by the Hydrometer; and there was
nearly the same Difference between the specific Gravity of unventilated
and ventilated Table Beer.

95. Tho’ from these Experiments it is manifest, that Fish die for want
of constant Supplies of fresh Air in the Water, yet when taken out of
the Water very lively, they soon die, notwithstanding the Surfaces of
their Gills are then exposed to the immediate Contact of the Air; which
shows that either the Air does not enter from the Gills to the Blood,
from the open Air, as it does from the Water; or that the Circulation
of the Blood is stopped by exchanging their proper Element, Water, for
Air; as the Circulation of the Blood of Land Animals is soon stopped by
immersing from Air into Water.

96. Hence we see the Benefit of frequently replenishing the Water with
fresh Air, which we find is necessary not only to preserve the Life
of Land Animals, but also of Fish; as also the Use of their Gills, to
spread in thin Sheets fresh Supplies of Water, that they may the better
come at the Air in the Water; for which Purpose both Sides of their
Gills are furrowed with many fine Furrows, not only thereby to enlarge
their Surfaces, but also more minutely to divide the Water, whereby to
come at the Air in it.

97. Whence we may reasonably infer, how requisite it is, in order to
keep the Blood in a salutary State, to have almost constant Supplies
of the Breath of Life, fresh Air, to mix with it: For if the principal
Use of the Gills were only to cool, and churn, and comminute the Blood,
Water devoid of Air could as well perform that Office, as Water repleat
with fresh Air. It must therefore be of Importance for all Animals to
have so necessary a vital Fluid fresh and pure, and not foul and putrid.

98. A Fisherman informing me that the Fish were apt to die in the
Well-boats, it occurred to me that it might, in a good measure, be
remedied, by fixing upright a Board of a proper Breadth at the Outside
of the Boat, as long as the Well is deep, on that side of the Well
which is next to the Stern, and opening at an Angle of about 45 Degrees
towards the Head; which, by checking the Course of the Stream of
the River near the Boat, will raise the Water a little, and thereby
cause it to run into the Well on that Side, and out on the other Side
of the Boat; and the Run of the Water thro’ the Well, will be more
accelerated, if a like Board is fixed in the same manner on the other
side of the Boat at the Side of the Well next to the Head of the Boat,
but opening towards the Stern at an Angle of 45 Degrees, by which means
the Water will be lowered on this, as much as it is raised on the
other Side of the Boat.----Another Means to have a brisker Current of
Water thro’ the Well, would be to moor the Boat in a fixed Position
across the Stream when it can conveniently be done. I am informed that
there are Passages from Head to Stern, for the Water to pass freely
thro’ the Fish-Well of some Vessels. We see, from the Event of the
above Experiments, the Importance of frequently changing the Water in
the Fish-Well of Ships, especially when there are many Fishes in it.
Hence also we see how salutary it is to Fish, to have the Surface of
the Water agitated into Waves by Winds, whereby Plenty of fresh Air
enters, and is blended with the Water.


_FINIS._



Transcriber’s Notes


A number of typographical errors were corrected silently.

New original cover art included with this eBook is granted to the public domain.



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