16 
HYDROCYAXIOACID GAS FUMIGATIOX IX CALIFORNIA. 
3 to 4 feet long sewed to the tent in the form of a right angle, as shown 
in figure 7, page 29. As fumigation tents should be pulled onto or off 
the trees in the direction in which the strips of cloth run, the rings 
should be so placed as to make this method of manipulation 
possible. This is accomplished by having two rings at either end of 
the tent and apart by about the width of the average-size tree treated. 
They should be placed from 3 to 5 feet back from the edge, the dis- 
tance depending on the size of the tent. A small link of chain 
called a "jingler" is usually attached to the ring, the sole purpose 
of which is to direct the operator to its location. By merely giving 
the sheet a shake this simple device enables the tent pullers to 
easily locate the rings on the darkest nights. 
Such a great strain is localized at the place 
where the rings are attached that it is well 
to have this part reenforced by stitching 
on an extra thickness of cloth. The same 
material of which the tent is constructed 
is very suitable. The strip used should be 3 
or 4 feet long. - 
BELL TEXTS. 
Fig. 3.— Method of attaching 
hooks to tent when covernig 
trees with aid of derricks: a, 
Tent gathered around ball of 
burlap or other suitable ob- 
ject; 6, stout cord for attach- 
ing ring; c, catch ring; d, hook 
on pulley block; e, lap link 
or "jingler." (From Morrill.) 
Originally the bell, or hoop, tent was the 
kind in use in California, and even now it en- 
joys a limited use in some countries. This 
tent is dome shaped, having the mouth held 
open by a circle of f-inch gas pipe. It is 
suited only for covering small trees. Plate I 
illustrates the character of this tent and the 
method of its manipulation. Experiments in 
California have resulted in the disuse of bell 
tents in favor of sheet tents, the latter style 
being not only easier of construction and manipulation, but also 
more easily kept in repair. 
GAS-PROOFIXG. 
The treatment of covers with various substances to increase their 
tightness has been in practice to a greater or less extent since the 
beginning: of fumigation. Linseed oil was one of the first tried. 
It renders the tents perfectly tight but greatly increases their weight. 
Experience has proved that tents so treated are liable to burning and 
rotting under the conditions to which they are subjected in the field. 
Treating tents with the mucilaginous concoction resulting from 
soaking the common cactus (Opuntia engelmanni) in water for 
two to four days was practiced to some extent 'during the nineties. 
Xumerous other methods have been tried, such as painting with a 
flexible paint: treating with glue dissolved in water: treating with 
