INJURIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 



489 



more convenient way of fixing up the schedule is to have a cylinder 

 made of zinc, with a narrow slot, the width of a row of figures, covered 

 by a glass, and a wooden roller on the inside, similar to a rolling pin. 

 Each end of the cylinder is closed by a cap with a hole in the center, 

 in which turn the handles of the wooden roller. The chart or 



FUMIGATION OF CITRUS TREES IN CALIFORNIA. 



DOSAGE SCHEDULE ■ FOR SODIUM CYANID 128-130 i (D08A0ES AEE IN ODNCES). 

 BT B. S. WOOLOM, SPECIAL AGENT. 



Fig. 487. 



-Fumigation dosage schedule 1 No. 1 for sodium cyanide. (After K. S. 

 Woglum, Bur. Ent., U. S. Dept. Agric.) 



schedule is attached to the roller so as to revolve in the cylinder. 

 The figures of the distances around are pasted along the top of the 

 slot to conform with the like numbers on the schedule. In finding 

 the dosage one has only to turn the roller until the distance over 

 shows at the left-hand end of the slot, the figure at the top of the 

 slot shows the distance around. In this way the chart is kepi per- 

 fectly dry and bright and the possibilities of making a mistake are 

 reduced to a minimum. This arrangement was first invented by 

 Mr. C. E. McFadden, who uses it on all of his chemical carts. 



MISCELLANEOUS EQUIPMENT 



Rubber gloves for handling the acid graduate and -cue, 

 pure rubber tubing for drawing off the acid, acid clamps or cut-offs 

 to control the flow, a pair of scales registering ounces, thermometer 

 and good lights are as necessary as any of the other equipment. 



