THE PINE-APPLE. 7 



have tried all these ways, and more besides, and consider 

 them all inferior to that represented by fig. 4. This is 

 a flat-bottomed open gutter or trough, 6 inches wide and 

 2 J inches deep, running the whole length of the house. 

 In the centre and along the whole length of the trough 

 is fixed a rain-water or lead pipe, 2^-inches in diameter. 

 This, as will be seen, is connected with the flow-pipe as 

 it leaves the boiler, and with the return-pipe at the 

 other end of the house. At the middle of the house a 

 tap is fitted into the 2^-inch pipe ; a flow of water from 

 the tap can be so adjusted as to let water sufficient trickle 



FiQ. 4. 



into the trough to keep it full and the small pipe nearly 

 immersed in water. The supply to the boiler being by 

 ball-cock, the small quantity of water that escapes 

 from the tap is constantly supplied. This apparatus 

 requires next to no attention, and heats regularly the 

 whole length of the house. In open gutters without 

 this small pipe, we have always found too much steam 

 at one end of the house and next to none at the other, 

 especially in long houses. The arrangement we recom- 

 mend is quite equal in heating power to a row of 4- 

 inch pipe. When atmospheric moisture is not required, 

 the water can be dried up out of the trough by simply 

 turning the tap. This system of supplying moisture is 



