GENERAL CULTURE OF STOVE PLANTS. 
59 
the heat mentioned vol. i, p. 146. It is by small tubes that the engines on the 
railways obtain their great heat, and Mr. Saul believes that small pipes will 
answer better than large boilers for heating hothouses, because of the little time 
required to procure the heat. 
The system of heating by hot water at Woburn Abbey answers exceedingly 
well, and may be a great help as a guide to those who wish to heat their houses in 
this manner. There are separate boilers and pipes to each division, or house, of 
the pinery (fig. 116). The boilers are placed in recesses in the back walls of the houses, 
the dimensions of which are two feet six inches long, one foot six inches wide, and 
one foot eight inches deep, of an oblong square. There are two pipes {b,b, see 
section) attached to each boiler, one near the top, and the other at the bottom ; the 
upper pipe is round, until it reaches the front of the house, w^here it forms a square 
of twelve inches broad by four inches diameter. 
Fig. 116. 
