GLASS STRUCTURES. 



83 



SOME THINGS TO REMEMBER IN CONNECTION WITH 

 BUILDING GLASS HOUSES FOR PLANTS. 



(1) That all joints should be made tight and so far as pos- 

 sible so placed that water will not lodge in them. 



(2) There should be just as much room in the beds and 

 as little in the paths as possible. 



(3) The glass should be as close to the beds as it can be 

 and allow room to manage the crops grown in them. It should 

 be of larger size for greenhouses than for hotbeds and in size not 

 smaller than 10x12 inches, laid on sash bars 11 inches apart. The 

 larger the glass the better. There is not so much breakage in 

 large as in small glass. 



(4) A permanent water supply is very desirable. 



(5) The glass should be of good quality, free from blisters, 

 bad waves or other imperfections and what is known as double 

 strength glass. 



(6) The heating arrangements should be sufficient to heat 

 the house easily in coldest weather; in other words, it should 

 be more than sufficient to maintain the proper temperature if 

 crowded. 



(7) Having the heating plant insufficient and then crowd- 

 ing it in severe weather, injures the heating plant and wastes 

 fuel besides being a trial of patierce. 



(8) The ventilators should ?je large and carefully fitted so 

 they will close tightly. When in tie roof they should be open at 

 the top. If they open at the bottnm the moisture that condenses 

 on the glass forms an ice ridge on them in cold weather and 

 prevents their shutting tight. 



(9) The smaller the sash bars and framing material in the 

 roof the more sunlight can reach the crop. 



(10) The greenhouse roof may be covered with movable 

 sash, but it is generally found most desirable to use permanent 

 sash bars. Where severe hail storms are frequent it might be 

 well to use movable saeh and take them off in the summer, but 

 such places are rare exceptions. It requires a very severe hail- 

 storm to break double strength glass, when at an angle, as in 

 a roof, and practically there is little risk from this source. 



(11) In the framing of greenhouses, for instances for pur- 



