New York Agricultural Experiment Station. 333 



Solubility of Zinc Arsenite as Indicated by the Water-Soluble Arsenious 



Oxide. 



Tap water 



Distilled water. . . . 

 Carbonated water. 



Shaken 

 ten days. 



Per ct. 



.50 

 .75 



Shaken 

 one day. 



Per ct. 



9.67 



Shaken 

 one hour. 



Per ct. 

 .50 

 .62 

 8.16 



The microscopic appearance of the particular lots of the two 

 poisons used in these experiments was as follows: The particles of 

 lead arsenate paste were non-crystalline, roughly spherical and 

 ranged in size from one to three microns. The particles of zinc 

 arsenite were slightly elongated, the shortest diameter being about 

 the same as that of the arsenate of lead. 



The materials employed in these tests were used in the following 

 quantities in fifty gallons of the diluted spray: lime-sulphur one and 

 one-fourth gallons of a solution testing 33° Beaume, bordeaux 

 mixture containing four pounds of copper sulphate and four pounds 

 of quicklime, soap two pounds, furniture glue one pound, glucose 

 twenty-two pounds and quicklime three pounds. 



The precipitation record at Geneva, N. Y., covering the period of 

 July 30 to August 24, when tests were conducted in the field, is as 

 follows : 



Rainfall 

 Date. in inches. 



July 31 06 



Aug. 2 07 



" 3 03 



" 5 08 



" 10 44 



" 12 08 



" 15 07 



" 18 65 



■ 19 24 



■ 20 04 



" 21 03 



'* 23 09 Total to Aug. 24, 1.88 inches. 



Total to Aug. 7, .24 inches. 



LABORATORY FEEDING TESTS. 



Test No. 1 , with Lina scripta. — This test was designed to deter- 

 mine the effects of zinc arsenite and arsenate of lead with and without 

 molasses. The beetles were confined in cages and supplied with 

 sprayed willow foliage. The observations were continued for nine 

 days. 



