GREENHOUSE 



show Uuit, L.uru., uu pl.tiit.,, c;iu.,La b., auicclnc yi.i, 

 roofs, occur iu lines and not iu isolated spots, burn 

 of the latter description being usually the result of 



GREENHOUSE 



691 



t\YO or more boilers are used, and are so arranged that 

 any of them can be cut off, the danger from this source 

 will be greatly lessened. The use of two or more small 

 boilers will also be found nmch more economical than 

 one large one during the fall or spring, when it will be 

 far cheaper to maintain a fire in one of the small boilers 

 than in a large one. 



In selecting a boiler, it is always desirable to have one 

 sufficiently large to afford the necessary heat without 

 forcing the fire, as this will not only give more satisfac- 

 tory results, but will result in the economy of fuel and 

 labor ind will prolong the life of the boiler Boiler 



Refraction of light rays 1 



irregular pane of glass 



w ikening i Int norition of tissue due to carelessness 

 111 the 111 tt 1 t A utilati n buuiiditv i t the atmos 

 I here 111 t It nhouses. 



11 the lower 

 , using in the 

 r testing m the 

 ismatic chiric 



iilh 



some definite ntio between the 

 he imo 11 t of hre smface m the 

 t I '1 biilei and the 



w-iter boilers, 

 between the 

 1 lie in larger 

 ud even more 

 \i\\ e constant 

 I 1 desirible to 



I I t f leaving the 



I urs in the se- 

 t houses it IS 

 1 1 grite much 

 I steini boilers 

 100 squiie feet 

 1 { 1 in average of 



hie suit iLcisLLnsidered equiva- 

 it being customarj to estimate 

 Hrgc b iilers and 18 feet m very 

 ne lioise power Thus m boilers 

 ■1 ot in s(|uaie feit of grate will 

 fett of heating or fire surface, 

 and this will 1 e sufficient toi nc-iilj 1 iW) ftet of radi- 

 ating surface where steam is used and as hot water 

 requires about two thirds raoie radiation a boiler of the 

 above size will answer for fi im 2 800 to ^ 000 square 

 feet of hot water radiation In using the aboA e figures 



makei^ 



boiki 

 whei 1 

 atten I 



about lo squaie ted 

 lent to a hoise p i^ 

 that 12 square feet 

 small ones will equ- 

 of medium size, an 



for 



nil 



dui ing 

 e an allowance 



artificial means t n heLtiu,< (Treen 



I modern stiuctuies are wanned 



t witer although hot air flues are 



While hot water is preferred for 



t I an be depended upon to 



I t when left for a numbei 



monly used for extensn e 



the houses is much less 



1 Steam boileis require 



1 t \ It 1 hcateis but wlien there 



: 000 ■ 



iif ^\ 



the 



