636 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. 



part, though considerable in the expanded form of a steam. Hence he was led to 

 try what would be the effect of causing an incessant shower of air to ascend 

 through the boiling liquor in a still ; and this he found on trial to be very consi- 

 derable. There was another circumstance also, which probably conduced to lead 

 him to this thought, viz. About six months before, Mr. Littlewood, a ship- 

 wright at Chatham, came to communicate to him an ingenious contrivance, soon 

 to sweeten stinking water, by blowing a shower of fresh air through a tin pipe 

 full of small holes, laid at the bottom of the water. By this means he said he 

 had sweetened the stinking bilge water in the well of some ships ; and also a butt 

 of stinking water in an hour, in the same manner as Dr. H. blew up air through 

 corn and gunpowder, as mentioned in the book on Ventilators. 



The method which he used to blow showers of air up through the distilling 

 water, was by means of a flat round tin box, 6 inches diameter, and an inch and 

 half deep ; placed at the bottom of the still, on 4 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 propor- 

 tionably larger, and have higher feet. And as the mouth of the still is too narrow 

 for the tin box to enter, which box ought to be within 2 inches as wide as the 

 bottom of the still; therefore the box may be divided into 2 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. 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, 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, a 4th of an inch distant from each other, and about the 

 '20th 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, fitted to receive, to put on, 

 and take off the lower end of a tin pipe, 20 inches long, and passed through 

 a hole in the head of the still : 4 inches of the upper end of this pipe., were 

 bent to a crook, almost at a right angle to the upright stem, 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 pi. 15, fiig. 8. 



The double bellows were bound fast to a frame, at the upper part of the iron 

 nose, and at the lower handle, the more commodiously to work them. And that 

 the upper half of the double bellows may duly rise and fall, to cause a constant 

 stream of air (besides the usual contracting spiral springs withinside), several flat 

 weights of lead must be laid 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 bel- 

 lows ; that by this means the weights may the more commodiously be put on or 



