16 
FUMIGATION FOB THE CITRUS WHITE ELY. 
sides of the octagon. The number of square yards of cloth required 
is about IS per cent, or between one-sixth and one-fifth less than 
for a square the sides of which are equal to the distance between 
parallel sides of the octagon. 
In California S-ounce army duck has been used almost exclusively for 
making sheet covers, while in Cape Colony. South Africa, a No. 10 
duck ranking in weight between 12-ounce and 15-ounce is commonly 
used. The heavier weights are not only more durable but presumably 
confine the gas better. A good grade of 6', -ounce drill, however, as 
shown later by the results obtained with a bell tent of this material, 
seems to be fully equal to the S-ounce duck commonly used in Cali- 
fornia. Until careful 
experiment- shall 
have determined the 
relative tightness of 
various weights of 
duck it is recom- 
mended that sheet 
tents be constructed 
throughout of 8- 
ounce duck or of 8- 
ounce duck in combi- 
nation wit ha "skirt " 
of 6^-ounce drill. 
The author has seen 
a sample of 8-ounce 
drill which is no more 
expensive than the 
best brands of duck 
■— -j of this weight, but is 
Fig. 1.— Plan for construction of octagonal sheet tent 50 feet across, evidently iai'Slipenor 
showing lines used in constructing octagon: A, C, side sections; B, 
central section of full-length strips; E, E, so-called "ends " of tent; 
S, S, so-called "sides" of tent; B, R, reinforcements; 1-21, strips 
of duck 29| inches wide, overlapped \ an inch at the seams. 
(Original.) 
a 
as regards tightness. 
Anyone contemplat- 
ing the ordering of 
a fumigating outfit 
should procure as many samples as possible of different brands of 
suitable cloth and select the closest woven brand. 
The strips when cut should be overlapped three-eighths or one-half 
inch and double stitched and all raw edges should be hemmed. In 
calculating the number and length of strips the overlapping will 
reduce the width of the cloth from three-fourths inch to 1 inch. As 
an illustration of the method of calculating the length of the strips 
used in making an octagonal tent of S-ounce duck. 50 feel may be 
taken as the desired size. This is equal to 600 inches and the width 
of the cloth, if 29.5 inches, will be reduced to 28.5 it" overlapped one- 
half inch at the seams. By dividing 28.5 inches into 600 inches the 
