;i6o On the UfeofSUam as a VeUchfor conveying Heat, 



being forced backwards into the ftcam boiler ; and, when this is done, and fome other ne- 

 ceflary precautions to prevent accidents are taken, fteam may be employed with great ad- 

 vantage for heating liquids ; and for keeping them hot, in a variety of cafes, in which fire, 

 applied immediately to the bottoms of the containing veffels, is now ufed. 



In dyeing, for inftance, and in brewing ; and in the procefles of many other arts and 

 manufa£tures, the adoption of this method of applying heat would be attended, not only 

 with a great faving of labour and of fuel ; but alfo of a confiderable faving of expence in 

 the purchafe and repairs of boilers, and of other expenfive machinery : for when fleam is 

 ufed inftead of fire for heating their contents, boilers may be made extremely thin and 

 light ; and, as they may eafily be fupported and ftrengthened by hoops and braces of iron, 

 and other cheap materials, they will coft but little, and feldom fland in need of repairs. 

 To thefe advantages we may add others of ftill greater importance : boilers intended to be 

 heated in this manner may, without the fmalleft difficulty, be placed in any part of a 

 room— at any diflance from the fire ; — and in fituations in which they may be approached 

 freely on every fide. They may moreover eafily be fo furrounded with wood, or with 

 other cheap fubflances which form warm covering, as mofl completely to confine the heat 

 within them, and prevent its efcape. The tubes by which the fleam is brought from the 

 principal boiler (which tubes may conveniently be fufpended jufl below the cieling of the 

 room) may, in like manner, be covered, fo as almoll intirely to prevent all lofs of heat by 

 tlie furfaces of them i and this to whatever diflances they may be made to extend. 



In fufpending thefe fleam tubes, care muft, however, be taken to lay them in a fituation 

 not perfeElly horizontal under the cieling, but to incline them at a fmall angle, making them 

 rife gradually from their jundlion with the top of a large vertical fleam tube, connedling 

 them with the fleam boiler, quite to their farthefl extremities : for, when thefe tubes are 

 fo placed, it is evident that all the water formed in them, in confequencc of the conden- 

 fation of the fleam in its pafTage through them, will run backwards and fall into the boiler, 

 inflead of accumulating in them, and obflru£ling the pafTage of the fleam, — which it would 

 not fail to do were there any confiderable bends or wavings, upwards and downwards, in 

 thefe tubes— or of running forward and defcending with the fleam into the vefTels con- 

 taining the liquids to be heated •,— which would happen if thefe tubes inclined dotuniuards, 

 iflflead of inclining upwards, as they recede from the boiler. 



(To be continued.) 



