THE petitioner sets forth, that, by various experiments, with considerable labor and expence, he has discovered a method of converting salt-water into fresh, in the proportion of 8 pints out of 10, by a process so simple that it may be performed on board of vessels at sea by the common iron cabouse with small alterations, by the same fire, and in the same time, which it used for cooking the ship's provisions; and offers to convey to the government of the United States a faithful account of his art, or secret, to be used by or within the United States, on their giving to him a reward suitable to the importance of the discovery, and, in the opinion of government, adequate to his expences, and the time he has devoted to the bringing it into effect.

In order to ascertain the merit of the petitioner's discovery, it becomes ne­cessary to examine the advances already made in the art of converting salt-water into fresh.

Lord Bacon, to whom the world is indebted for the first germs of so many branches of science, had observed, that, with a heat sufficient for distillation, salt will not rise in vapour, and that salt-water distilled, is fresh. And it would seem that all mankind might have observed, that the earth is supplied with fresh-water chiefly by exhalation from the sea, which is in fact an insen­sible distillation effected by the heat of the sun. Yet this, though the most obvious, was not the first idea in the essays for converting salt-water into fresh. Filtration was tried in vain, and congelation could be resorted to only in the coldest regions and seasons. In all the earlier trials by distillation, some mixture was thought necessary to aid the operation by a partial precipitation of the salt, and other foreign matters contained in sea-water. Of this kind were the methods of Sir Richard Hawkins, in the 16th century, of Glauber, Hauton and Lister, in the 17th, and of Hales, Appleby, Butler, Chapman, Hoffman and Dove, in the 18th: nor was there any thing in these methods worthy noting on the present occasion, except the very simple still contrived ex­tempore by Capt. Chapman, and made from such materials as are to be found on board every ship, great or small. This was a common pot with a wooden lid of the usual form, in the center of which a hole was bored to receive per­pendicularly a short wooden tube, made with an inch and half auger, which perpendicular tube received at it's top, and at an acute angle, another tube of wood also, which descended till it joined a third, of pewter, made by rolling up a dish, and passing it obliquely through a cask of cold water. With this sim­ple machine he obtained two quarts of fresh-water an hour, and observed, that the expence of fuel would be very trifling, if the still was contrived to stand on the fire along with the ship's boiler.

In 1762, Dr. Lind proposing to make experiments of several different mix­tures, first distilled rain-water, which he supposed would be the purest, and then sea-water, without any mixture, which he expected would be the least pure, in order to arrange between these two supposed extremes the degree of merit of the several ingredients he meant to try. "To his great surprise," as he confesses, the sea-water distilled without any mixture, was as pure as the rain-water. He pursued the discovery and established the fact, that a pure and potable fresh-water may be obtained from salt-water by simple distil­lation without the aid of any mixture for fining or precipitating it's foreign contents. In 1767, he proposed an extempore still, which, in fact, was Chap­man's, only substituting a gun-barrel instead of Chapman's pewter tube, and the hand-pump of the ship to be cut in two obliquely, and joined again at an acute angle, instead of Chapman's wooden tubes bored express; or, in­stead of the wooden lid and upright tube, he proposed a tea-kettle (without It's lid or handle) to be turned bottom upwards over the mouth of the pot, by way of still-head, and a wooden tube leading from the spout to a gun-barrel passing through a cask of water, the whole luted with equal parts of chalk and [...] moistened with salt-water.

With this apparatus of a pot, tea-kettle and gun-barrel, the Dolphin, a 20 gun ship, in her voyage round the world, in 1768, from 56 gallons of sea-water, and with 9lb. of wood and 69lb. of pit-coal, made 42 gallons of good fresh water at the rate of 8 gallons an hour. The Dorsetshire, in her passage from Gibraltar to Mahon, in 1769, made 19 quarts of pure water in 4 hours with 10lb. of wood: And the Slambal, in 1773, between Bombay and Bengal, with a hand-pump, gun-barrel and a pot, of 6 gallons of sea-water made 10 quarts of fresh water in 3 hours.

In 1771, Dr. Irvin, putting together Lind's idea of distilling without a mixture, Chapman's still, and Dr. Franklin's method of cooling by evapora­tion, obtained a premium of 5000l. from the British parliament. He wet his tube constantly with a mop instead of passing it through a cask of water: He enlarged its bore also in order to give a freer passage to the vapour, and thereby encrease its quantity by lessening the resistance or pressure on the evaporating surface: this last improvement was his own, it doubtless contributed to the success of his models; and we may suppose the enlargement of the tube to be useful to that point at which the central parts of the vapour, passing through it, would begin to escape condensation. Lord Mulgrave used his method in his voyage towards the North Pole in 1773, making from 34 to 40 gallons of fresh water a day, without any great addition of fuel, as he says.

M. de Bougainville in his voyage round the world, used, very successfully, a still which had been contrived in 1763, by Poyssonier, so as to guard against the water being thrown over from the boiler into the pipe by the agitation of the ship. In this one singularity, was, that the furnace or fire box was in the middle of the boiler, so that the water surrounded it in contact. This still, however, was expensive and occupied much room.

Such were the advances already made in the art of obtaining fresh from salt water, when Mr. Isaacks, the petitioner, suggested his discovery.

As the merit of this could be ascertained by experiment only, the Secretary of State asked the favor of Mr. Rittenhouse, President of the American Phi­losophical Society, of Dr. Wistar, professor of chemistry in the college of Phi­ladelphia, and Dr. Hutchinson, professor of chemistry in the university of Pennsylvania, to be present at the experiments. Mr. Isaacks fixed the pot of a small cabouse, with a tin cap and strait tube of tin passing obliquely through a cask of cold water; he made use of a mixture, the composition of which he did not explain, and from 24 pints of sea water, taken up about 3 miles out of the Capes of Delaware at flood tide, he distilled 22 pints of fresh water in 4 hours, with 20lb. of seasoned pine, which was a little wetted by having lain in the rain.

In a 2d experiment of the 21st of March, performed in a furnace and five gallon still at the college, from 32 pints of sea water he drew 31 pints of fresh water in 7 h. 24 min. with 51lb. of hickory which had been cut about six months. In order to decide whether Mr. Isaacks's mixture contributed in any and what degree to the success of the operation, it was thought proper to repeat his experiment under the same circumstances exactly, except the omission of the mixture. Accordingly on the next day the same quantity of sea water was put into the same still, the same furnace was used, and fuel from the same par­cel. It yielded, as his had done, 31 pints of fresh water in 11 min. more of time and with 10lb. less of wood.

On the 24th of March Mr. Isaacks performed a 3d experiment. For this, a common iron pot of 3 ½ gallons was fixed in brick work, and the flue from the hearth wound once round the pot spirally, and then passed off up a chim­ney. The cap was of tin, and a strait tin tube of about two inches diameter, passing obliquely through a barrel of water, served instead of a worm. From 16 pints of sea water he drew off 15 pints of fresh water in 2 h. 55 min. with 3lb. of dry hickory and 8lb. of seasoned pine. This experiment was also re­peated the next day, with the same apparatus and fuel from the same parcel, but without the mixture. Sixteen pints of sea water yielded in like manner 15 pints of fresh, in 1 min. more of time and with half a pound less of wood. On the whole, it was evident that Mr. Isaacks's mixture produced no advantage, ei­ther in the process or result of the distillation.

The distilled water in all these instances was found on experiment to be as pure as the best pump water of the city. Its taste indeed was not as agreeable, but it was not such as to produce any disgust. In fact, we drink in common life, in many places, and under many circumstances, and almost always at sea, a worse tasted, and probably a less wholesome water.

The obtaining fresh from salt water, was for ages considered as an important desideratum for the use of navigators. The process for doing this by simple distillation is so efficacious, the erecting an extempore still with such utensils as are found on board of every ship is so practicable, as to authorize the assertion, that this desideratum is satisfied to a very useful degree. But though this has been done for upwards of 30 years, though its reality has been established by the actual experience of several vessels which have had recourse to it, yet nei­ther the fact nor the process is known to the mass of seamen, to whom it would be the most useful, and for whom it was principally wanted. The Secretary of State is therefore of opinion, that since the subject has now been brought under observation; it should be made the occasion of disseminating its know­ledge generally and effectually among the seafaring citizens of the United States. The following is one of the many methods which might be proposed for doing this. Let the clearance for every vessel sailing from the ports of the United States, be printed on a paper, on the back whereof shall be a printed account of the essays which have been made for obtaining fresh from salt wa­ter, mentioning shortly those which have been unsuccessful, and more fully those which have succeeded; describing the methods which have been found to answer for constructing extempore stills of such implements as are generally on board of every vessel, with a recommendation, in all cases where they shall have occasion to resort to this expedient for obtaining water, to publish the re­sult of their trial in some gazette on their return to the United States, or to communicate it for publication to the office of the Secretary of State, in order that others may, by their success, be encouraged to make similar trials, and be benefitted by any improvements or new ideas which may occur to them in practice.