86 ON HEATING GREENHOUSES BY MEANS OF HOT WATER. 



ARTICLE IX. 



ON HEATING GREENHOUSES BY MEANS OF HOT WATER, 

 AS DESCRIBED BY C. C, OF SOMERSETSHIRE, Page 255. 



BY A. B. C, OF CORNWALL. 



C. C.'s observations on this head appear to me to contain exactly 

 the quantity of information calculated to puzzle and mislead all 

 who know nothing of this subject, without giving the slightest 

 information to those who are at all. acquainted with it. Having 

 put up an apparatus myself last winter, which answers well. I 

 send you the result of my experience, presuming, however, that I 

 only offer it to those who are ignorant of the subject, as I was before 

 I turned my attention to it. 



In the first place, the thing cannot be done unless the principle is 

 understood as well as the modus operandi. The principle is that 

 there should be a constant circulation of the hot water, whether it 

 flows through pipe or tank. The circulation keeps the temperature 

 equal throughout the whole pipe, and therefore over the whole house, 

 and unless this circulation is secured you may have one end of your 

 house warm and the other freezing at the same time. 



The mode of obtaining this circulation will be readily understood 

 by a little attention to the following diagram and explanation. 



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Let A B C D represent the boiler ; Z represent the fireplace ; 

 xxxx water all round the fireplace; E G H K M F the water-pipe, 

 of which one end at E enters the top of the boiler, the other end at 

 F enters the boiler at or near the bottom. The water-pipe must be 

 quite horizontal, the branch G H being on the same level as the 

 branch K M, and the whole pipe being above the level of the boiler 

 (except the small parts near the boiler, which descend to it). Now, 

 supposing the fire to be lighted, the top part of the boiler is heated 



