564 - PHILOSOPHICAL TKANSACTIONS. [aNNO J 742. 



plied by some other aperture ; in order to which, one or more holes are made 

 through the brick work in the side of the ash-pit ; and tubes of lead or copper 

 fitted closely in the holes, and made fast, are laid from thence into the well 

 and other parts of the ship ; by which means the air next the bottom of the 

 tubes rushes through them, and the foul air succeeding is transmitted through 

 the fire, and passes off, without offending, by means of the chimney; and a 

 supply of fresh air from the other parts of the ship continually fills the place of 

 the former, the fire requiring a constant support, which support will be want- 

 ing, not only during the continuance of the fire, but while any warmth remains 

 in the fire-place, copper, or brick-work, as was observed on board the hulk at 

 Deptford, where the draught of air through the tube lasted above 12 hours 

 after the fire was taken away. This being considered, as the dressing the provi- 

 sions for a number of people will take up some hours every day, the warmth of 

 the brick-work and flues will continue a draught of air from one day to the 

 next. Mr. Sutton proposes thus to circulate the air by the same, and no greater 

 expence of fire than is used for the necessities of the ship. The operation of 

 the machine will be equally useful in large as small ships ; for the greater the 

 number of people they have on board, the larger quantity, and longer continu- 

 ance, of the fire will be necessary to dress the provisions ; and therefore there 

 will be required a greater quantity of air to support that fire. 



There is also, especially in large ships, not only a copper, but also a fire- 

 grate like those used in kitchens : that the heat and smoke of this also may not 

 be useless, an iron tube may be fixed behind the grate, and inserted quite 

 through the deck, so that one end of it will stand about a foot, or little more, 

 in the chimney above the brick-work, and the other will enter into the hold, 

 or any other part of the ship ; so that the upper end being heated, the draught 

 of air will be supplied from below, as in the other case. This likewise was tried 

 on board the hulk, with an iron tube about 2 inches and a half in diameter, and 

 the lighted candles held at the bottom of this tube were extinguished as fast as 

 by any of the other. 



It may be objected, that a number of tubes take up too much room, especially 

 in merchants' ships, and are subject to be broken or injured by loading or un- 

 loading : to remedy which, it is advisable, that only one tube of a convenient 

 size be made fast unto the side of the ash-pit, and, as soon as it comes through 

 the main deck, to compress it, not too close ; and it may be divided into as 

 many ramifications as may be thought necessary, especially as the bread-room, 

 store-room, &c. cannot be kept too sweet, a branch for each of these, and 

 these branches be carried between the beams which support the deck, till they 



