562 JOURNAL OF ECONOMIC ENTOMOl.OGY [Vol. 9 



One student maintained that a prominent fruit-grower was forced 

 to return several hundred pounds of arsenate paste to the manufacturer, 

 and it was observed that the frozen paste was much more granular 

 than the original material. 



In talking the question over with Mr. A. L. Lovett, Station Ento- 

 mologist, it was agreed that a number of letters should be written to 

 prominent entomologists and manufacturers, asking them to state if in 

 their opinion the arsenates of lead were harmed by freezing. Nineteen 

 letters were received in answer to the inquiry. Eight of these men (42 

 per cent) took the stand that freezing had no effect on the efficiency 

 of the arsenate sprays. Six specialists (31.6 per cent) stated that there 

 was no doubt in their minds as to the harmful effects obtained and 

 under no conditions should the frozen arsenates be used. Five 

 writers (26.3 per cent) were either doubtful or confessed to no definite 

 knowledge regarding the question. 



Mr. Richardson of the New Jersey Experiment Station stated that 

 Mr. C. S. Cathcart, Station Chemist, 



obtained a sample of frozen arsenate of lead and made a careful analysis of it. He 

 was unable to discern any change in the amount of arsenic oxide, water soluble ar- 

 senic, etc., in this sample and came to the conclusion that freezing did not in any way 

 alter the chemical composition of the material. 



W. E. Britton, State Entomologist for Connecticut, presented the 

 following statement : 



We know that it must freeze, and we have never hesitated to use it in our work the 

 following season. Sometimes the mechanical condition is changed somewhat, but 

 this comes more from drying than from freezing. If it becomes dry, as you know, it 

 is apt to be lumpy, and it is hard work to again pulverize it, so that it will remain in 

 suspension or so that the particles will be finely divided. 



A prominent manufacturer wrote as follows: 



As you know, arsenate of lead in the form that ours is in, known as the "hydrogen," 

 is a very tight combination, and a very stable compound. We have experimented a 

 number of times in freezing our material, and then mixing it with water, for suspen- 

 sion tests. Also, freezing it, and then drying it out, so that it was water-free, and 

 breaking it up. In all our experiments we have never been able to alter the physical 

 and mechanical values of our arsenate of lead paste thi-ough freezing. It never broke 

 down in any way, causing an injurious effect on foliage. 



In support of the harmlessness of using frozen arsenate the manager 

 and entomologist for another chemical manufacturing house states: 



So far as I have seen, practically all brands of lead paste of recent manufacture 

 lose nothing in efficiency on being frozen. With some brands the soUd matter has a 

 tendency to settle more hard in the bottom of the container and consequently is more 

 difficult to get into proper suspension after freezing, but I have purposely made sev- 

 eral tests on rather extensive areas and in every case the results in worm control were 



