Diameters for cylindrical chimney-flues, for given heights and boiler capacities (R. C. Carpenter)

Four-cornered chimneys are considered to be equivalent to cylindrical chimneys when the sides equal the diameter.

Effects of wind in cooling glass (Leuchars)

 Velocity of Wind per hour Time Required to lower Temperature from 120° to 100° F. 3.26 miles.... 2 : 58 minutes 5.18 miles..... 2 : 16 minutes 6.54 miles......... 1 : 91 minutes 8.86 miles........... 1 : 66 minutes 10.90 miles....... 1 : 50 minutes 13.36 miles........... 1 : 25 minutes 17.97 miles........... 1 : 08 minutes 20.45 miles...... 1 : 00 minutes 24.54 miles..... : 91 minutes 27.27 miles........... : 81 minutes

Table of radiation for glass (Dean 1)

1 From Dean's " Greenhouse Heating," by permission of " Domestic Engineering."

Radiating surface of pipes of different lengths and diameters

Method for finding boiler capacity for cast-iron pipe

Table showing how to get at the amount of 31/2-inch cast-iron pipe necessary to heat greenhouse to temperature wanted, when outside temperature is at zero, Fahrenheit (Lord & Burnham Co.)

For 10° below zero, add 10 per cent.; for 20° add 20 per cent., and so on. For 70° to 75° divide square feet of glass and equivalent by 1.8. For 65° to 70° divide square feet of glass and equivalent by 2.28. For 60° to 65° divide square feet of glass and equivalent by 2.62. For 55° to 60° divide square feet of glass and equivalent by 3. For 50° to 55° divide square feet of glass and equivalent by 3.46. For 45° to 50° divide square feet of glass and equivalent by 4. For 40° to 45° divide square feet of glass and equivalent by 4.67. For 35° to 40° divide square feet of glass and equivalent by 5.5.

For 2-inch work, use same table and same example and multiply the amount of 31/2-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

 • Day Night Asparagus plumosus....... 70° 60° Azalea, Indian... 65° 50° Bulbs (hyacinth, tulip, etc.) 60° 45° Carnation 60° 50° Calla.................. 70° 60° Chrysanthemum....... 55° 45° Cineraria........ 65° 50° Cyclamen....... 65° 50° Ferns, as maiden hair...... 75° 60° Lily (Easter).............. 65° 55° Lily of the valley (forcing)........ 90° 90° Palms house........ 75° 60° Primulas 65° 50° Rose 65° 55° Smilax 60° 50° Stocks. 65° 50° Sweet pea............ 60° 50° Violet................. 50° 40°