An Account of the Distilling Water Fresh from Sea-Water by Wood-Ashes. By Capt. William Chapman: In a Letter to John Fothergill, M. D.

If my stay here had been longer, I had continued my observations; and perhaps should have made some discoveries. It belongs to the academicians of Bordeaux to push these observations further, if they think proper. From the Entrance of the river of Bourdeaux, the 4th of August, 1756. Peyffonel. LXXXVII. An Account of the distilling Water fresh from Sea-water by Wood-ashes. By Capt. William Chapman: In a Letter to John Fothergill, M.D. Whitby, 10th 2d mo. Feb. 1758. Read April 13, 1758. THY kind acceptance of my last emboldens me to inform thee, how, on my return from a voyage to the north part of Russia, I procured a sufficient quantity of fresh water from sea-water, without taking with me either instruments or ingredients expressly for the purpose. Some time in September last, when I had been ten days at sea, by an accident (off the north cape of Finland) we lost the greatest part of our water. We had a hard gale of wind at south-west, which continued three weeks, and drove us into 73° lat. During this time I was very uneasy, as knowing, if our passage should hold out long, we must be reduced to great straits; for we had no rains, but frequent fogs, which yielded water in very small quantities. I now blamed blamed myself for not having a still along with me (as I had often thought no ship should be without one). But it was now too late; and there was a necessity to contrive some means for our preservation. I was not a stranger to Appleby's method: I had also a pamphlet wrote by Dr. Butler, intituled, An easy Method of procuring of fresh Water at Sea. And I imagined, that soap might supply the place of capital lees, mentioned by him. I now set myself at work, to contrive a still; and ordered an old pitch-pot, that held about ten quarts, to be made clean: my carpenter, by my direction, fitted to it a cover of fir deal, about two inches thick, very close; so that it was easily made tight by luting it with paste. We had a hole thro' the cover, in which was fixed a wooden pipe nearly perpendicular. This I call the still-head: it was bored with an augre of 1 ½ inch diameter, to within three inches of the top or extremity, where it was left solid. We made a hole in this, towards the upper part of its cavity (with a proper angle) to receive a long wooden pipe, which we fixed therein, to descend to the tub in which the worm should be placed. Here again I was at a loss; for we had no lead pipe, nor any sheet-lead, on board. I thought, if I could contrive a strait pipe to go thro' a large cask of cold water, it might answer the end of a worm. We then cut a pewter dish, and made a pipe two feet long; and at three or four trials (for we did not let a little discourage us) we made it quite tight. We bored a hole thro' a cask, with a proper descent, in which we fixed the pewter pipe, and made both holes in the cask tight, and filled it with sea-water: the pipe stuck without the cask three inches on each side. Having now got my apparatus in readiness, I put seven quarts of seawater, and an ounce of soap, into my pot, and set it on the fire. The cover was kept from rising by a prop of wood to the bow. We fixed on the head, and into it the long wooden pipe above-mentioned, which was wide enough to receive the end of the pewter one into its cavity. We easily made the joint tight. I need not tell thee with what anxiety I waited for success: but I was soon relieved; for, as soon as the pot boiled, the water began to run; and in twenty-eight minutes I got a quart of fresh water. I tried it with an hydrometer I had on board, and found it as light as river-water; but it had a rank oily taste, which I imagine was given it by the soap. This taste diminished considerably in two or three days, but not so much as to make it quite palatable. Our sheep and fowls drank this water very greedily without any ill effects. We constantly kept our still at work, and got a gallon of water every two hours; which, if there had been a necessity to drink it, would have been sufficient for our ship's crew. I now thought of trying to get water more palatable; and often perused the pamphlet above-mentioned, especially the quotation from Sir R. Hawkins's voyage, who "with four billets distilled a hogshead of water wholesome and nourishing." I concluded he had delivered this account under a veil, lest his method should be discovered: for it is plain, that by four billets he could not mean the fuel, as they would scarce warm a hogshead of water. When, ruminating on this, it came into my head, that he burnt his four billets to ashes, and with the mixture of those ashes with sea-water he distilled a hogshead of fresh water wholesome and nourishing. Pleased with this discovery, I cut a billet small, and burnt it to ashes; and after cleaning my pot, I put into it a spoonful of those ashes, with the usual quantity of sea-water. The result answered my expectations: the water came off bright and transparent, with an agreeable pungent taste, which at first I thought was occasioned by the ashes, but afterwards was convinced it received it from the resin or turpentine in the pot, or pipes annexed to it. I was now relieved from my fears of being distressed thro' want of water; yet thought it necessary to advise my people not to be too free in the use of this, whilst we had any of our old stock remaining; and told them, I would make the experiment first myself; which I did, by drinking a few glasses every day without any ill effect whatever. This water was equally light with the other, and lathered very well with soap. We had expended our old stock of water before we reached England; but had reserved a good quantity of that which we distilled. After my arrival at Shields, I invited several of my acquaintance on board to taste the water: they drank several glasses, and thought it nothing inferior to spring-water. I made them a bowl of punch of it, which was highly commended. I have not the convenience of a still here, or should have repeated the experiment for the conviction of some of my friends: for as to myself, I am firmly persuaded, that wood-ashes mixed with sea-water will yield, when distilled, as good fresh water as can be wished for. And I think, if every ship bound a long long voyage was to take a small still with Dr. Hales's improvements, they need never want fresh water. Wood-ashes may easily be made, whilst there is any wood in the ship; and the extraordinary expense of fuel will be trifling, if they contrive so that the still may stand on the fire along with the ship's boiler. I shall think myself sufficiently recompensed, if any hints here may tend to the relief of my brother sailors from the dismal extremity of want of water; an extremity too little regarded by those, who have never experienced it. P. S. During my passage from Russia we very rarely had any aurora borealis; and those few we saw were faint, and of short continuance: at which I was much surprised; for about ten years ago, being in a high north latitude, we had very beautiful ones almost every night in the month of September; which exceeded any I have seen described in the Philosophical Transactions, or Memoires de l'Academie Royale. Wm. Chapman.