$0 On the. XJfe of Steam 



the fleam-boiler, will defcend through the fteam-tubes and 

 mix with the liquids in the veflels below ; but when the open 

 ends of thefe tubes project upwards within the (team con- 

 ductor, though it be but to a final) height above the level of 

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

 It is not riecetfary to obferve here, that, in order that the 

 ends of the fteam-tubes may project within the horizontal 

 conductor, the diameters of the former mull be coniiderably 

 lefs than the diameter of the latter. 



To prevent the lofs of heat arifing from the cooling of the 

 different tubes through which the fleam' mud pafs in coming 

 from the boiler, all thole tubes mould be well defended from 

 the cold air of the atmoi'phcre by means of warm covering; 

 but this may eafily be done, and at a very trifling expenie. 

 The horizontal conductors may be inclofed within fquare 

 wooden lubes, and furrounded on every fide by charcoal- du ft, 

 fine fawduft, or even by wool ; and the (team-tubes and prime 

 conductor may be furrounded, firft by three or four coatings 

 of itrong paper, firmly attached to them by pafte or glue, and 

 covered with a coating of varnifh, and then by a covering of 

 thick coarfc cloth. It will likewife be advifable to cover the 

 horizontal conductors with feveral coatings of paper; for, if 

 the paper be put on to them while 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 effectually the heat, but alfo by adding 

 very much to the ftrength of the tube, and rendering it un- 

 necessary to employ thick and ftrong fheets of metal in the 

 conftruction of it. 



However extraordinary and incredible it may appear, I can 

 affert it as a fact, which 1 have proved by repeated experi- 

 ments, that if a hollow tube, conftructed of fheet copper J s 

 of an inch in thicknefs, be covered by a coating only twice 

 as thick, or T 'c °f an inch In thicknefs, formed of layers of 

 itrong paper, firmly attached to it by good glue, the ftrength 

 of the tube will be more than doubled by this covering. I 

 found by experiments the molt unexceptionable and de- 

 cifive, (of which I intend, at fome future period, to give to 

 the public a full and detailed account,) that the ftrength of 

 paper is fuch, when feveral (beets of it are firmly attached 

 together with glue, that a folid cylind of this fubftance, 

 the tranfverfe fection of which mould amount to only one 

 Superficial inch, would fuftain a weight of 30,000 lbs. avoir- 

 dupois, or above i§ tons, iufpended to it, without being 

 pulled afuuder or broken. The ftrength of hemp is ftill 



much 



