﻿ARSENICALS. 



17 



centages of the total lead present in the sample: For the one-hour 

 period, 3 per cent; for the one-day period, 7 per cent; and for the 

 three-day period, 7.6 per cent. The results for water-soluble ar- 

 senic in the combinations are lower than those for water-soluble ar- 

 senic in the arsenicals alone. It is evident that the excess lime of the 

 Bordeaux combined with part of the soluble arsenic present in the 

 arsenates, forming insoluble calcium arsenate. 



The results show that Bordeaux mixture and the arsenates of lead 

 and calcium, as well as Paris green, are compatible, that a soluble ar- 

 senate, such as sodium arsenate, may be used in quantities large 

 enough to act as an insecticide in combination with ordinary Bordeaux 

 mixture, and that the excess lime of the Bordeaux will combine with 

 the soluble arsenic to form insoluble calcium arsenate. 



ARSENATES AND KEROSENE EMULSION. 



As kerosene emulsion is occasionally used in combination with acid 

 lead arsenate and may be used with calcium arsenate, a series of 

 experiments was undertaken to determine whether detectable chemical 

 changes take place in these combinations. 



A kerosene emulsion was prepared according to the following direc- 

 tions : 6 One liter of commercial kerosene oil and 1 ounce of sodium 

 fish-oil soap in water were mixed, and the resulting emulsion was 

 diluted to 10 liters. 



A series of 300 cubic centimeter flasks were filled with this emulsion 

 and 0.8 gram of acid lead arsenate (sample 39) or 0.667 gram of cal- 

 cium arsenate (sample 57) was added to each of the flasks, with the 

 exception of the control flasks. Mixtures of the arsenates alone 

 and of the emulsions alone were used for controls. The mixtures 

 were agitated at 35° C. for periods of one hour, one day, and three 

 days. They were filtered immediately and the filtrates were tested 

 for arsenic. The average figures only are recorded in Table 7. 



Table 7. — Soluble arsenic in filtrates from combinations of arsenicals with Bordeaux 

 mixture and with kerosene emulsion. 



Sample 

 No. 



Material analyzed . 



Total ar- 

 senic (As) 

 in sample 

 taken. 



Soluble arsenic (As) found 

 after standing for — 



Percentage of total ar- 

 senic (As) found soluble 

 after standing for — 





lhour. 



lday. 



3 days. 



1 hour. 



lday. 



3 days. 



25 





Grams. 



0. 1709 



.1938 



.1753 



.1709 



Grams. 



Grams. 



Grams. 



0. 1650 

 .0066 

 . 00034 

 .0048 

 .00006 



.00001 



.00046 



.00000 



.00018 



.0122 



.0740 



Per cent. 



Per cent. 



Per cent. 

 96.55 



64 













3.41 



57 













0.20 



39 













2.81 



61 



Bordeaux mixture 















Sodium arsenate (25) plus 

 Bordeaux (61^ 



.1709 

 .1938 

 .1753 

 .1709 

 .1753 

 .1709 



0. 00095 

 00113 

 .00003 

 . 00051 

 .0018 

 .0332 



0. 00001 

 .00053 

 .00005 

 .00030 

 .0095 

 .0768 



0.56 

 .58 

 .02 

 .30 



1.03 

 19.43 



0.00 

 .27 

 .03 

 .IS 



5.42 

 44.94 



.00 



— 



Paris green (64) plus Bor- 

 deaux (61) 



.24 



— 



Calcium arsenate (57) plus 

 Bordeaux (61) 



.00 



— 



Acid lead arsenate (39) plus 



.11 



— 



Calcium arsenate (57) plus 

 kerosene emulsion 



Acid lead arsenate (39) plus 

 kerosene emulsion 



6.96 

 43.30 



e Taken from U. S. Dept. Agr. Farmers' Bull. 958, p. 28. 

 27476°— 23— Bull. 1147 3 



