56 



FUMIGATION INVESTIGATIONS IN CALIFORNIA. 



may be accomplished, in regions of heavy dev^s or fogs, by simply 

 leavino- 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 Cal- 

 ifornia in marking walnut 

 bags. If the ink is too 

 thick to mark freely, it 

 may be diluted with kero- 

 sene. Printer's ink does 

 not cause the cloth to de- 

 teriorate. A mixture of 

 lampblack and tuipentine may also be used with entire safety. The 

 latter, however, will sometimes rub off to a slight extent. 



Fig. 



19.— Carboy with handles attached to facilitate pouring 

 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 fumigators 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^ 



