of heating Hot-houses by hot Water. 



261 



and calculations ; for, were this known, we should at once have 

 a rule for erecting an apparatus for houses of any dimensions. 

 Until this be established, the following "rule of thumb" plan, 

 which I have just adopted, will answer. ( Fig. 53. a b.) 



EXPLANATION OF REFERENCES. 



A, Section of the boiler, showing the second range of" pipes {b c). Suppose 

 them all to be 4-inch pipes, the height of the boiler would be 32 in., allow- 

 ing 4 in. between the pipes. It should be of copper. 



B, The new valve, which should be of copper or brass, and made exactly 

 to fit the boiler. For the above boiler, it should be 18 in. long, and have 

 two circular holes (ff ) cut in it of the diameter of the pipes, so that when 

 it is pushed down into the boiler the holes may be opposite the pipes. This 

 portion of the boiler, and the valve, should be nicely ground together, but 

 not so tight, but that the latter may be turned round by the handle {e, and 

 in^g. D, i) at the top. There is also an opening left at the top to allow 

 the steam to escape, and not endanger the vessel by bursting. 



c, The top of the valve (d). The arrow points directly over the holes, so 

 that should it be turned for the purpose of closing the pipes, the exact pro- 

 portion closed is visible ; and to entirely shut the communication, the head 

 of the arrow should be the contrary way of the pipes. 



D, The new boiler, with the valve half drawn up; the bottom is larger 

 and concave (say 18 in. diameter) to receive more heat, and the returning 

 pipe (/} is 4 in. above the bottom. If the pipes are 4 in. diameter, the boiler 

 from 7)1 should be 12 in. diameter, and 20 in. high from the top to the bot- 

 tom, i. e. from n to n. 



k, The delivering pipe. 



E, The lateral pipe, with a part enlarged to admit the valve (which is 

 of brass) to open to the diameter of the pipe. 



s, The valve placed diagonally, so that its own weight may shut it. A 

 collar of brass is soldered to the pipe, and ground to fit the valve, so as to 

 be water-tight, 



r, The hinge. 



t, Wire attached at the bottom to open it ; this wire passes through 9 

 small tube (q), and may be fastened in any way most convenient. 



The dotted lines represent the valve open. The small tube should be as 

 high as the top of the boiler, otherwise the water would escape through it. 



The proportions mentioned are only as general guides, and the drawings 

 are not to any scale. 



s a 



