On the XJfe of Steam at a Vehicle for einvey'wg HeaL 169 



TKis Jieam tule may either defcend •within the vejfel to which it belongs, or en the outfide 

 efity as (hall be found moft convenient. If it comes down on the outfide of the veffel, it 

 muft enter it at its bottom, by a (hort horizontal bend; and its junction with the bottom 

 of the veflel muft be well fecured, to prevent leakage. If it comes Idown into the veflel, 

 on the infide of it, it muft defcend to the bottom of it, or at leaft to within a very fewr 

 inches of the bottom of it ; otherwife the liquid in the v^el will not be uniformly and 

 equally heated. 



When the fteam tube is brought down on the infide of the containing veflel, it may 

 either come down perpendicularly, and without touching the fides of it, or it may come 

 down on one fide of the veflel, and in contaft with it. 



When feveral fteam tubes, belonging to different containing veflels, are connefted with 

 one and the fame horizontal fteam condudlor, the upper end of each of thefe tubes, inftead 

 of being fimply attached by foldering to the under fide of the condu£tor, muft enter, at 

 leaft one inch, within the cavity of it ; otherwife the water refulting from a condenfation 

 of a part of the fteam in the condu£lor, by the cold air which furrounds it, inftead o£ 

 finding its way back into the fteam boiler, will defcend through the fteam tubes and mis 

 with the liquids in the veflels below ; but when the open ends of thefe tubes projedl up- 

 wards within the fteam conduftor, though it be but to a fmall height above the level of its 

 under fide, it is evident that this accident cannot happen. 



It is not neceflliry to obferve here, that, in order that the ends of the fteam tubes may 

 projeft within the horizontal condnBoTi the diameters of the former muft be confiderably 

 lefs than the diameter of the latter. 



To prevent the lofs of heat arifing from the cooling of the different tubes through which 

 the fteam muft pafs in coming from the boiler, all thofe tubes fliould be well defended from 

 the cold air of the atmofphere, by means of warm covering ; but this may eafily be done, 

 and at a# very trifling expence. The horizontal condudtors may be enclofed within fquare 

 wooden tubes, and furrounded on every fide by charcoal duft,— fine fawduft, — or even by 

 wool ; and the fteam tubes, and prime conduftor, may be furrounded firft by three or four 

 coatings of ftrong paper, firmly attached to them by pafte or glue, and covered with a 

 coating of varnifli, and then by a covering of thick coarfe cloth. It will likewife be ad- 

 vifable to cover the horizontal conductors with feveral coatings of paper, for if the paper 

 be put on to them wjiile it is wet with the pafte or glue ; and if care be taken to put it on 

 in long flips or bands, wound regularly round the tube in a fpiral line, from one end of it 

 to the other, this covering will be ufeful, not only by confining more effeftually the heat,, 

 but alfo by adding very much to the ftrength of the tube, and rendering it unneceflary to 

 employ thick and ftrong flieets of metal in the conftrudtion of it. 



However extraordinary and incredible it may appear, I can afl*ert it as a fafl:, which I 

 have proved by repeated experiments, that if a hollow tube, conftrufted of (heet copper 

 ^■^ of an inch in thicknefs, be covered by a coating of only twice as thick, or -/^ of an inch 

 in thicknefs, formed of layers of ftrong paper, firmly attached to it by good glue, the 



Vol... v.— AucvsT 1801. ^ ftrength 



