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tract them, instead of doing them any service, are likely in the end, to do them a great deal of harm.
Yours, &c. 1756, Feb.
XVII. Dr. Hales's method of obtaining fresh Sea-water. THE effect of causing an incessant shower of air to ascend through the boiling liquor in a still, to my surprise, I found to be very considerable. The method I used was by means of a flat round tin box, six inches diameter, and an inch and a half deep ; which is placed at the bottom of the still on four knobs half an inch high, to make room for the liquor to spread over the whole bottom of the still. The mouth of the still being too narrow for the tin box to enter, which should be as wide as the bottom of the still, it may be di. vided into two parts with a hinge at one side, and a clasp at the other, to fix it together when in the still. The air pipe which passes through the head of the still, will help to keep the air-box from moving to and fro by the motion of the ship, or three or four small spurs may be fixed to the sides of the air-box, and reach to the sides of the still. The cover and sides of the air-box were punched full of very small holes,a quarter of an inch distant from each other. On the middle of the lid was fixed a nosle, above half an inch wide, fitted to receive, to put on, and take off the lower end of the tin pipe, which was 20 inches long, and passed through a hole in the head of the still. Four inches of the upper end of this pipe were bent gibbet-fashion, almost at right angles to the upright, in order to the uniting it with the enlarged nose of a pair of bellows, by means of a short calfskin pipe. This tin air-box, and many more, were made by Mr. Tedway, tinman, against the Mews Gate, CharingCross.
The double bellows were bound fast to a frame at the upper part of the iron nose, and at the lower handle,to work them more commodiously. 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 fat weights of lead must be laid on the upper part of the bellons near the handle, with a hole in their middle, to fix them on an
upright iron pin, fastened on the bellows; so the weights may be commodiously put on or taken off, according to the different depths of water in the still. Thus, if the depth of the water in the still be 12 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. Where the stills are fixed in ships, the air may be conveyed to them from the bellows through a small leathern pipe, distended with spiral coils of wire, or bamboo canes, or broad small wooden pipes, like hollow fishing rods.
The quantity of water distilled in a given time by this way of continual ventilation, is, at a medium, more than double of the usual distillation. It is to be hoped, therefore, that so considerable an increase will be of great benefit to navigation, and save much fire.
By ventilation with a 20-gallon still, 240 gallons, or a ton and 24 gallons, may be distilled in 20 hours, with little more than two bushels of coals, allowing for the time of heating the still full of cold water. A ton in 24 hours will more than suffice for a 60 gun ship with 400 men, and larger may have proportionably larger stills. Ten-gallon stills will produce 120 gallons in 20 hours, and 5-gallon ones, 64 gallons.
Dr. Butler proposes pouring in more sea-water through a funnel fixed in the head of the still, when more than half has been distilled off, whereby it will soon acquire a distilling heat, adding chalk in such proportion as shall be found requisite. The funnel hole must be stopped with a cork, or small copper plate, turning on and off upon a pin.
The waste of fuel will be less in proportion in large, than in small stills, and the wider the still head is, so much the more liquor will be distilled.
It is of great importance to keep all parts of the still clean and free from rust or verdigrease of the copper.
Now supposing, that in a 60 gun ship, the 110 tons of water for four months use, were distilled at the expence of three bushels of coals per ton, this would take 9 chaldrons, or about 13. tons weight, or 94 tons less than the 110 tons of store-water, and allowing 24} tons for the still-water casks and coals, there will be 70 tons weight of stowage sared thereby
XVIII. Experiments for sweetening ill-tasted Milk and stinking
Water by Ventilation, &c. by Dr. Hales.
The method of blowing showers of air up through liquors, will be of considerable use in several other respects as well as distillation.
August 23, four quarts of ill-tasted milk, from a cow which had fed 48 hours upon cabbage leaves, drinking very little water in that time, were put into a leaden vessel, which was heated in a large boiler, whereby the milk was kept scalding hot, then in ten minutes ventilation it was perfectly cured of its ill taste.
Three gallons of stinking Jessop's well water were ventilated. On the first blowing, the smell of the ascending vapours was very offensive, which abated much in five minutes. In twenty minutes the water was sweet both in smell and taste.
July 20, three gallons of stinking sea-water were ventilated. In five minutes it was much sweetened, and no ill smell in the ascending air, though at first it was very offensive. At the end of ien 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, which was from the bitumen, &c.
It is to be suspected that the stinking water which is drunk in ships may promote that putrid distemper, the scurvy, as well as some others; and that putrid waters in marshy countries may be the cause of agues, as well as the putrid air they breathe. This method, therefore, of sweetening stinking water by blowing showers of air up through it, inust be
beneficial. Live fish may well be carried many miles by blowing now and then fresh air up through 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; but stinking water will presently kill fish.
Much of the oil may be got out of tar-water by blowing up showers of air through it when scalding hot, for 15 or 20 minutes, the longer the better; the less volatile and more salutary acid remaining,
XIX. Anecdote of the late Duke of Montague. MR. URBAN We have often been amused with stories of the whims and frolics that great men have exercised upon little ones to the no small astonishment and perplexity of the said little men, and the unspeakable delight of themselves and their company. The late Duke of Montague was remarkable for these achievements of wit and humour, which he conducted with a dexterity and address peculiar to himself. I send you an account of one of them for the entertainment of your readers, though I doubt whether there is one among them all to whom it will give as much pleasure as it gave
Soon after the conclusion of the late peace he had observed, that a middle-aged man, in something like a military dress, of which the lace was much tarnished and the cloth worn thread-bare, appeared at a certain hour in the park, walking to and fro in the Mall with a kind of mournful solemnity, or ruminating by himself on one of the benches, without taking any more notice of the gay crowd that was moving before him, than of so many en niets on an ant-hill, or atoms dancing in the sun.
This man the duke singled out as likely to he a fit object for a frolic. He began, therefore, by making some inquiry concerning him, and soon learned that he was an unfortunate poor creature, who having laid out his whole stock in the purchase of a commission, bad behaved with great bravery in the war, in hopes of preferment; but upon the conclusion of the peace had been reduced to starve upon half-pay. This the duke thought a favourable circumstance for his purpose; but he learned, upon farther inquiry, that the captain having a wife and several children, had been reduced to the necessity of sending them down into Yorkshire, whither he constantly transmitted them one moiety of his half-pay, which would not subsist them nearer the metropolis, and reserved the other moiety to keep himself upon the spot, where alone he could hope for an opportunity of obtaining a more advantageous situation. These particulars afforded a new scope for the duke's genius, and he immediately began his operations.
After some time, when every thing had been prepared, he watched an opportunity as the captain was sitting alone, buried in his speculations on a bench, to send his gentleman to him with his compliments, and an invitation to dinner the
next day. The duke having placed himself at a convenient distance, saw his messenger approach without being perceived, and begin to speak without being heard; he saw his intended guest start at length from his reverie, like a man frighted out of a dream, and gaze with a foolish look of wonder and perplexity at the person that accosted him, without seeming to comprehend what he said, or to believe his senses when it was repeated to him till he did. In short, he saw with infinite satisfaction all that could be expected in the looks, behaviour, and attitude, of a man addressed in so abrupt and unaccountable a manner; and as the pended upon the man's sensibility, he discovered so much of that quality on striking the first stroke, that he promised himself success beyond his former hopes. He was told, however, that the captain returned thanks for the honour intended him, and would wait upon his grace at the time appointed.
When he came, the duke received him with particular marks of civility, and taking him aside with an air of great secresy and importance, told him that he had desired the favour of his company to dine chiefly upon the account of a lady, who had long had a particular regard for him, and had expressed a great desire to be in his company, which her situation made it impossible for her to accomplish, without the assistance of a friend ; that having learned these particulars by accident, he had taken the liberty to bring them together, and added, that he thought such an act of civility, whatever might be the opinion of the world, could be no imputation upon his honour. During this discourse, the duke enjoyed the profound astonishment and various changes of confusion that appeared in the captain's face, who, after he had a little recovered himself, began a speech with great solemnity, in which the duke perceived he was labouring to insinuate in the best manner he could, that he doubted whether he was not imposed upon, and whether he ought not to resent it; and therefore to put an end to his difficulties at once, the duke laid his hand upon his breast, and very devoutly swore, that he toid him nothing that he did not believe upon good evidence to be true.
When word was brought that dinner was served, the captain entered the dining-room with great curiosity and wonder, but his wonder was unspeakably increased when he saw at the table his own wife and children. The duke had begun his frolic by sending for them out of Yorkshire, and had as