56 
FUMIGATION INVESTIGATIONS IN CALIFORNIA. 
may be accomplished, in regions of heavy dews or fogs, by simply 
leaving the tents exposed in the open for a few days. Dipping in 
water or sprinkling by 
means of a hose and then 
allowing the tent to dry 
in the sunshine will an- 
swer the same purpose 
if repeated several times. 
The shrinkage of a new 
45-foot tent will some- 
times be as much as 3 
feet. Tents marked be- 
fore being shrunk will 
have erroneous gradu- 
ations. 
The most satisfactory 
material to use in mark- 
ing tents is diluted 
printer's ink. This ink 
is commonly used in ( Jal- 
ifornia in marking walnut 
bags. If the ink is too 
thick to mark freely, it 
maybe diluted with kero- 
sene. Printer's ink does 
not cause the cloth to de- 
teriorate. A mixture of 
lampblack and turpentine may also be used with entire safety. The 
latter, however, will sometimes rub off to a slight extent. 
Fig. 19.— Carboywith handles attached to facilitate pourin 
the acid and carrying the carboy. (Original.) 
A DEVICE FOR COVERING FUMIGATION GENERATORS. 
During the course of this investigation much effort has been 
directed toward perfecting a device for attachment to the top of the 
commonly used open-style fumigation generator that will serve to 
interrupt the direct rise of the hydrocyanic-acid gas. The result of 
these efforts, in which the writer was greatly aided by Mr. Frederick 
Maskew, is shown in figure 21. The device itself consists of a copper 
cover of such size as to make it available for use with any of the 
regular-pattern generators now employed by the lumigators of 
southern California. It is stamped in a concave form from a sheet 
of copper, with corrugations to permit the escape of gas. The shape 
is such as to conform to the size of the opening of generators of dif- 
ferent capacities and also to direct the course of the escaping gas 
downward and distribute it uniformly through the lower part of the 
