HOT WATER APPARATUS. 



37 



doors, P, to exclude the external air. The boilers represented in these 

 four figures are intended for houses of moderate dimensions, and the 

 manufacturer states them to be the most economical yet made. 



Section of a Circular Boiler. 



Figure 5 represents the section of a circular boiler, with an additional 

 chamber and flue surrounding the lower part ; this boiler is circular, and 

 only two feet eight inches in diameter across the bottom, in the clear of 

 the brick work, and three feet high. During each winter," says Mr. 

 Thomson, I made use of this boiler, with which I heated four himdred 

 and forty eight feet of three and four inch pipe, which warmed two large 

 greenhouses or stoves, sixty feet by sixteen, and sixty feet by fourteen, 

 together with two pits sixty feet by eight, and sixty feet by six. The 

 whole were kept up at their respective temperatures during the severest 

 part of last winter without any difficulty, the only fuel required being 

 cinders or very small coke, ^ith the refuse cuttings fi'om the nurser^^ and 

 at no time did it requu'e more than four baskets of such fuel in the twenty 

 four hours," 



