326 Of the Use of Steam 



braces of iron, and other cheap materials, they will cost 

 but little, and seldom stand in need of repairs. 



To these advantages we may add others of still greater 

 importance. Boilers intended to be heated in this man- 

 ner may, without the smallest difficulty, be placed in any 

 part of a room, at any distance from the fire, and in 

 situations in which they may be approached freely on 

 every side. They may, moreover, easily be so surrounded 

 with wood, or with other cheap substances which form 

 warm covering, as most completely to confine the heat 

 within them and prevent its escape. The tubes by 

 which the steam is brought from the principal boiler 

 (which tubes may conveniently be suspended just below 

 the ceiling of the room) may, in like manner, be cov- 

 ered so as almost entirely to prevent all loss of heat by 

 the surfaces of them, and this to whatever distances 

 they may be made to extend. 



In suspending these steam-tubes, care must, however, 

 be taken to lay them in a situation not perfectly horizon- 

 tal^ under the ceiling, but to incline them at a small 

 angle, making them rise gradually from their junction 

 with the top of a large vertical steam-tube, which con- 

 nects them with the steam-boiler, quite to their farthest 

 extremities ; for, when these tubes are so placed, it is 

 evident that all the water formed in them, in conse- 

 quence of the condensation of the steam in its passage 

 through them, will run backwards, and fall into the 

 boiler, instead of accumulating in them and obstructing 

 the passage of the steam (which it would not fail to do 

 were there any considerable bends or wavings, upwards 

 and downwards, in these tubes), or of running forward 

 and descending with the steam into the vessels contain- 

 ing the liquids to be heated, which would happen if 



