19 
to 30 years old and averaging 30 feet in height, about 50 can be treated 
in a night of ten or twelve hours, with an equipment of 12 or 15 tents, 
the cost being about 75 cents per tree. It is not practicable to treat 
trees above 30 feet in height. 
The handling of the bell tents is simple and needs no further descrip- 
tion, but the large tents are not so easily operated, and the method of 
adjusting the great flat octagonal sheets over the trees, while simple 
enough when once understood, Lab Mise 
will have, perhaps, some inter- i 
est for Eastern fruit growers 
who may desire to experiment 
with the hydrocyanic acid gas. 
The only machinery employed 
consists of two simple up- 
rights, with attached blocks 
and tackle (fig. 2). The up- 
rights are about 25 feet high, 
of strong Oregon pine, 2 by 4 
inches, and are provided at 
the bottom with a braced cross- 
bar to give them strength and 
to prevent their falling to 
either side while the tent is 
being raised. A guy rope is 
attached to the top of each pole 
and held to steady it by two of 
the crew stationed at the rear 
ofthe tree. The tent is hoisted 
by means of two ropes 70 
feet long, which pass through 
blocks, one fixed at the top of 
the pole and the other free. 
The tent is caught near the 
edge by taking a hitch around 
some solid object, such as a 
green orange, about which the 
cloth is gathered. By this 
means the tent may be caught 
anywhere without the trouble 
of reversing and turning the heavy canvas to get at rings or other 
fastenings attached at particular points. The two remaining members 
of the operating crew draw the tent up against and over one side of the 
tree by means of the pulley ropes sufficiently to cover the other side 
of the tree when the tent falls. The poles and tent together are then 
allowed to fall forward, leaving the tent in position. Sufficient skill is 
soon acquired to carry out rapidly the details of this operation, so that 

Fia. 2.—Method of hoisting sheet tent (after Craw). 
