GREENHOUSE FUMIGATION WITH HYDROCVANIC-ACID GAS. 5 



METHOD OF COMPUTING THE CUBICAL CONTENTS OF EVEN AND THREE- 

 QUARTER SPAN GREENHOUSES. 



It is essential in every instance that the cubical contents of the 

 greenhouse to be fumigated be determined accurately, and the fol- 

 lowing is a simple method of arriving at these figures: To facilitate 

 matters a diagram indicating the necessary dimensions of the green- 

 house should be made. (See figs. 2 and 3.) 



To secure the cu])ical contents of the even-span greenhouse (fig. 2)> 

 compute the number of square feet in the rectangle a and in the right- 

 angle triangles 6 and c and multiply the sum of the tliree by the 

 length of the greenhouse. For example, a = 5X20 = 100 square feet, • 

 J = 5X10^2 = 25 square feet; 1 and c = 5X 10-^2 = 25 square feet. 

 a-|-6 + c=150 square feet. 150 squiare feet X 100 feet (length of 

 house) = 15,000 cubic feet, cubical contents of the greenhouse. 



1" f '~ ' c 



I _^ 



3 a- 



I d 



I 



4 ^. 



Fig. 2. — Diagram showing method of computing 

 cul)ical contents of even-span greenhouse. 



Fig. 3.— Diagram showing method of computing 

 cubical contents of three-quarter-span green- 

 house. 



To secure the cubical contents of the three-quarter-span greenhouse 

 (fig. 3), multiply the simi of the rectangles a and d and right-angle 

 triangles 6 and c by the length. For example a. = 6x8 = 48 square 

 feet; (?=18X5 = 90 square feet; 6 = 6X4-^2 = 12 square feet; and 

 (•=18x7-^2 = 63 square feet. a-|-(i! + 6 + c = 213 square feet. 213 

 square feet X 100 feet (lengtli of house) = 21,300 cubic feet, cubical 

 contents of greenhouse. 



In estimating the cubical contents of a greenhouse it is not necessary 

 (() make iillowances for the space occupied by the benches, pots, etc. 



TIME FOR FUMIGATION. 



Fumigation should be conducted not earlier than one houi' after 

 sunset and should not be attempted when the wind is high. It is 

 undesirable to fumigate during extremely cold nights, when the 

 thermometer is registering near zero, owing to the necessity of ven- 



by the perpendicular and dividi; the 



1 To calculate the area of a right-angle triant le, multiply the 

 product by two. 



