Bulletin 340] 



CONTROL OF THE POCKET GOPHER 



347 



a special apparatus which forces the gas down the hole. This is ac- 

 complished by a hand bellows attached to the top of a tank that con- 

 tains the carbon bisulphide. The air is forced through a pipe from the 

 bellows to the tank, where it passes over the bisulphide and is carried 



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Fig. 4. — a,i. Vertical "treadle" or "pan" of regular trap; heavy dotted 

 lines show places to bend vertical treadle to form horizontal treadle c. 



out through a rubber hose which is pushed do\vn the open hole and 

 then tightly surrounded by dirt. Contrivances of this sort, such as 

 the Eureka Squirrel Exterminator, are on the market. Then there are 

 gopher "bombs" which, when lighted and placed in the burrows and 

 covered, are supposed to generate a poisonous gas that will kill the 

 gopher. As with carbon bisulphide, the gas often fails to reach the 

 gopher because of obstruction and elevations in the winding burrows. 

 Experiments have shown that with gasoline at 20 cents and carbon 

 bisulphide at 90 cents a gallon, the bisulphide was more effective and 

 cheaper than gasoline. 



5. ENCOUEAGEMENT OF THE GOPHEE'S NATURAL ENEMIES 



Comparatively few ranchers realize the full value of barn owls and 

 gopher snakes as allies in their war on gophers. A pair of nesting 

 barn owls was foujid by the writer to catch from three to six gophers 

 a day for their young. No one who has ever counted the number of 

 rodents brought in by a pair of these owls during a single season would 

 ever doubt their value as gopher destroyers. 



On May 13, 1914, near Mendota, Fresno County, Mr. John G. 



