393 



Grapes. 



torn. The stratum of water surrounding the fire is about an inch 

 thick. 



Fig. 442. 



Fig. 442 a. 



Forty-three pipes, from the fire through the upper plate, carry the 

 hot air and smoke to the expanded smoke pipe, and heat the water 

 with great rapidity. The amount of fuel required has been found to 

 be onty two-thirds the amount for other heaters in common use. 



The size of the boiler for the larger house is about twenty inches 

 in diameter, and three and a half feet high, and smaller for the other 

 house. The hot water pipes connecting with the tanks should be 

 three inches in diameter inside for the small house, and four inches 

 for the larger. Six tons of coal only were used throughout the 

 entire season of spring propagation, for both houses. 



Fig. 443- 



An improvement in cheapness of construction for a lean-to cold 



