Forcing-House Miscellanies. 385 



friction of steam, however, the efficiency is still greater, as shown 

 in the summarj figures (D). ~ From these considerations we include 

 thqt 



lU. Ill heating hy water in closed circuits^ a high exjyansion 

 tank may increase the efficiency hy allowing the water to hecome 

 hotter throughout the system, and givitig a better circulation. 



If we were to compare the fluctuations^ or up and down tempera- 

 tures, in the various systems, by a study of the average ther- 

 mometer readings in all the pipes — as shown in the last column in 

 the tables — we should find the following : 



E. Extreme Average Fluctuations. 



Water, low tank 123° 201° 



Water, bigh tank 162" 201° 



Steam 122° 221'> 



The steadiest temperature was maintained in the water under the 

 greater pressure, whilst the greatest fluctuations were with steam. 

 This poor showing of the steam, however, is mostly the result of the 

 unadaptability of the apparatus to steam heating. In our first tests, 

 the fluctuations were greater with water, whilst in the second, when 

 this small heater was used, they were about the same with steam and 

 water. 



Now, the total warming power of the different systems is deter- 

 mined by the average temperatures of the pipes and the amount of 

 fuel consumed. In this test we used 100 lbs. of hard coal daily in 

 each of the three series of tests ; and inasmuch as this fuel o^ave 

 more heat when applied to steam than when applied to water in the 

 same apparatus, we must conclude that under these conditions, now 

 repeated for two winters and with the initial advantage in favor of 

 water, steam was the more efficient and economical. If, however, 

 more piping had been added when water was used, the final results 

 might have been in favor of water, particularly of the greater 

 pressure. 



Illuminating gas as fuel. — Common illuminating gas is much 

 used for fuel in small stoves, water heaters, and the like. It seemed 

 that it might be used to advantage in heating small conservatories 

 attached to dwellings, because it is difficult to secure a very small 

 circulator which has a fire-pot big enough to hold a bright fire all 

 night. I accordingly put a Perfection Water Heater (made by the 

 Milwaukee Gas Stove Co.) in my cellar to heat a small conservatory 



25 



