On the TJfe of Steam at a Vehicle for eonvey'ing Heat, 1 71 



the containing veflel af, or very near, its bottom, it is evident that this (team muft be fuf- 

 "ficiently ftrong, or claftic, to overcome, not only the preflure of the atmofphere, but alfo 

 the additional preflure of the fuperincumbent liquid in the veflel ; the fteam boiler muft, 

 therefore, be made ftrong enough to confine the fteam, when its elafticity is fo much in- 

 creafed by means of additional heat, as to enable it to overcome that refiftance. This in- 

 creafe of the elaftic force of the fteam need not, however, in any cafe, exceed a preflure of 

 five or fix pounds upon a fquare inch of the boiler, or one third party or one half, of an 

 atmofphere. 



It is not necefl'ary for me to obferve here, that in this, and alfo in all other cafes, where 

 fteam is ufed as a vehicle for conveying heat from one place to another, it is indifp^nfably 

 neceflary to provide fafety valves of two kinds ; — the one for letting a part of the fteam 

 cfcape, when, on the fire being fuddenly increafed, the fteam becomes fo ftrong as to 

 expofe the boiler to the danger of being burft by it 5 — the other for admitting air into the 

 boiler, when, in confequence of the dinainution of the heat, the fteam in the boiler is con- 

 denfed, and a vacuum is formed in it ; and when, without this valve, there would be dan- 

 ger, either of having the fides of the boiler cruftied, and forced inwards by the preflure of 

 the atmofphere from without ; or of having the liquid in the containing veflels forced up- 

 wards into the horizontal fteam conduftorsj and from thence into the fteam boiler. This 

 laft mentioned accident, however, cannot happen, unlefs the cocks in fome of the fteam 

 tubes happen to be open. — The two valves efi'edtually prevent all accidents. 



The reader will, no doubt,, be more difpofed to pay attention to what has here been ad- 

 vanced, on this intcrefting fubjeft, when he Is informed that the propofed fcheme has 

 already been executed on a very large fcale, and with complete fuccefs } and that the above 

 details are little more than exaft defcriptions of what aftually exifts. 



A great mercantile and manufa£luring houfe at Leeds, that of Meflrs. Gott, and Co. had 

 the courage, notwithftanding the mortifying prediction of all their neighbours, and the 

 ridicule with which the fcheme was attempted to be treated, to ere£t a dyeing houfe, on a 

 very large fcale indeed, on the principles here defcribed and recommended. 



On my viCt to Leeds the laft fummer, I waited on Mr. Gott, who was then mayor of 

 the towp, and who received me with great politenefs, and fliewed me the cloth halls, and 

 other curloCties of the place ; but nothing he fliewed me interefted me half fo much as his 

 own truly noble manufaQory of fuperfine woollen cloths. I had feen few manufa£lories 

 fo extenfive, and none fo complete in all its parts. It was burnt to the ground the year 

 before I faw it, and had juft been rebuilt, on a larger fcale ; and with great improvements 

 in almoft every one of its details. The reader may eafily conceive that I felt no fmall de- 

 gree of fatisfa£tion on going into the dyeing houfe, to find it fitted up on principles which 

 I had had fome ftiare in bringing into repute, and which Mr. Gott told me he had adopted 

 in confequence of the information he had acquired in the perufal oi m.-^ feventh eflay. He 

 aflured me that the experiment had anfwered, even far beyond his moft fanguine expedta- 

 tions ; and, as a ftrong proof of the utility of the plan, he told me, that his next door 



Z 2 . neighbour, 



