198 



GREENHOUSE AND WINDOW-GARDEN WORK 



Method for finding boiler capacity for cast-iron pipe 



Table showing how to get at the amount of 3^-inch cast-iron pipe necessary to 

 heat greenhouse to temperature wanted, when outside temperature is at zero, 

 Fahrenheit (Lord & Burnham Co.) 



For 10 

 For 70 

 For 65 

 For 60 

 For 55 

 For 50 

 For 45 

 For 40 

 For 35 



below zero, add 10 per cent, 

 to 75 divide square feet of 

 to 70 divide square feet of 

 to 65 divide square feet of 

 to 60 divide square feet of 

 to 55 divide square feet of 

 to 50 divide square feet of 

 to 45 divide square feet of 

 to 40 divide square feet of 



; for 20 add 20 per cent., and so on. 

 glass and equivalent by 1.8. 

 glass and equivalent by 2.28. 

 glass and equivalent by 2.62. 

 glass and equivalent by 3. 

 glass and equivalent by 3.46. 

 glass and equivalent by 4. 

 glass and equivalent by 4.67. 

 glass and equivalent by 5.5. 



For 2-inch work, use same table and same example and multiply the amount 

 of 3>^-inch pipe obtained by 1.68. 



In proportioning glass surface, all wall surface must be figured in ; about 5 

 feet of wall equals 1 foot of glass. 



Customary temperatures in which plants are grown under glass 



Various Estimates and Recipes 



Percentage of rays of light reflected from glass roofs at various angles of 

 divergence from the perpendicular (Bouguer) 



1 2.5 per cent 



10 2.5 per cent 



20 2.5 per cent 



30 2.7 per cent 



40 3.4 per cent 



50 5.7 per cent 



60 11.2 per cent 



70 22.2 per cent 



80 41.2 per cent 



85 54.3 per cent 



