16 MASS. EXPERIMENT STATION BULLETIN 303 



in proportion to the amount of alkali present. A large excess of alkali reduced the 

 concentration of precipitated copper in the spray and consequently the amount 

 of soluble copper in the gassed residues. 



The toxic salt is presumably calcium cuprocyanide CaCu.) (CN)45H20 or a 

 similar soluble copper salt of cyanide. 



LITERATURE CITED 



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 . 3. Guba, E. F. Injury to greenhouse plants from hydrocyanic acid gas, follow- 

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the greenhouse. Amer. Produce Grower 1:12. 1926. 



5. Hodgman, C. D., and Lange, N. A. Handbook of chemistry and physics. 



10th ed. Chemical Rubber Publishing Co., Cleveland, Ohio. 1922. 



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 Research 33:741-751. 1926. 



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 Sta. Bui. 254. 1929. 



10. , and Gilligan, G. M. Chemical hydrated lime for the preparation of 



Bordeaux mixture. Phytopath. 17: 571-572. 1927. 



11. , and Gilligan, G. M. Classification of copper fungicides. Phytopath. 



18:455-458. 1928. 



12. Pickering, S. U. Copper salts and their behavior with alkalis. Jour. Chem. 



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14. Ridgway R. Color standards and color nomenclature. Washington, D. C. 



1912. ' 



15. Williams, H. E. The chemistry of cyanogen compounds. 423 pp. .\. Churchill, 



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Publication ok this Document Approved hy Commission on Ad-minisfration and Fina.nce 

 .3M-l-'34. No, 2tiK. 



