184 Agricultural Experimknt Station, Ithaca, N. Y. 



The steam boiler consumed during this time 6,691 pounds of 

 coal, and the hot water boiler 5,251 pounds. The steam boiler 

 heats about 2,500 square feet of surface. The hot water boiler 

 heats about 1,700 square feet. The following comparisons are 

 therefore obtained: 



In surface heated, 



Hot water: Steam:: 1: 1.47 — 



In coal used, 



Hot water: Steam:: 1: 1.27 — 



This shows a consumxytion of about fifteen per cent more coal 

 per 100 square feet of surface heated by the hot water heater than 

 by the steam heater. The average temperature is slightly higher 

 in the hot-water house than in the steam-houses, but it was also 

 more variable. In the colder parts of the night it went much 

 lower, for twice during the winter plants .were chilled in this 

 house, while nothing of the kind occurred in the steam-housed. As 

 a matter of fact it has been difiicult to main tain a suitable tem- 

 perature in the hot-water house whenever the weather was cold. 

 These fluctuations in greenhouses are seldom indicated by obser- 

 vations taken at two or three stated intervals dming the day. The 

 space heated by the hot water causes considerable bending in the 

 pipes, while the faU is rather slight, conditions which are unfavor- 

 able to water heating; for every curjve and angle interferes 

 greatly with the movement of water. The results indicate that 

 while hot water may equal steam in simple and straight runs, it 

 is not so well adapted to use under varying and unfavorable cir- 

 cumstances and in long houses. No definfte conclusion as to the 

 relative merits of the two systems as to coal consumption can be 

 made from these observations, for the conditions are not such as 

 to give a genuine comparison. But thej^ are an indication that 

 steam is more economical under the conditions here present; and 

 our conditions are similar to those of most commercial forcing 

 establishments. 



It is impossible to determine whether this saving of coal in our 

 steam plant is due to greater economy of steam as compared with 



