April, '15] 



SAFRO: NICOTINE SULPHATE-BORDEAUX 



201 



second. On nine days the precipitation ranged from .02 to 1.33 inches. 

 In other words, the variations in weather were sufficient for leaf injury 

 to become e^ddent T\dthin the three weeks during which the plants 

 were under investigation. 



Nicotine Sulphate Not Decomposed. ^ — Two hours after mak- 

 ing up the Nicotine Sulphate-Bordeaux combination it was analyzed 

 for nicotine. The chemical record follows : 



"The percentage of nicotine, by calculation, in the Nicotine Sulphate-Bordeaux 

 mixture should be 409/10,000 of 1%. (19.255 grams of Nicotine Sulphate— 41% 

 nicotine by gravimetric analj'sis, containing 7.8945 grams of nicotine, were added to 

 19255 grams of Bordeaux mixture. This gives a calculated percentage of 409/ 10,000 



ofirj. 



'^The nicotine was distilled from a weighed quantity of Nicotine Sulphate-Bordeaux 

 mixture with steam after the addition of Caustic Soda. The Nicotine in the distillate 

 obtained was determined by the regular Gravimetric Method. 



"The actual analysis gives the nicotine content to be 413/10,000 of 1%." 



All the nicotine, apparently, was recovered from the combination. 



Nicotine Not Precipitated. — The chemical record follows: 



"A portion of the Nicotine Sulphate-Bordeaux mixture was removed, filtered and 

 washed with distilled water. The filtrate was tested for nicotine, and washing con- 

 tinued until no more nicotine passed through the filter. 



"(50 c.c. of original Nicotine Sulphate-Bordeaux was used; the wash water amount- 

 ing to about 400 c.c, used in portions of 40 c.c. each.) 



"The filter paper with its copper precipitate was introduced into a distilling flask, 

 caustic soda added, and steam distillation conducted as in regular nicotine distilla- 

 tions. 



"The distillate was tested for nicotine with Silicotungstic Acid and not the slightest 

 precipitate was obtained. 



"(Silicotungstic Acid will show a precipitate with nicotine in a dilution of one in 

 300,000.)" 



Injury Following the Combination Explained. — Instances have 

 been reported in which foliage injury followed the use of the combina- 

 tion, and these cases of injury were often the bases of recommenda- 

 tions to appl}^ the two sprays separately. 



The cases of injury apparently belong to the same category as the 

 injur}^ sometimes following the combination of Nicotine Sulphate with 

 lime sulphur or with arsenate of lead or arsenite of zinc. The latter 

 combinations are widely recommended; still, occasional reports of 

 injury are heard. These cases are perhaps explained, as far as the 

 combination itself is concerned, when we consider that under certain 

 conditions lime sulphur, arsenate of lead and arsenite of zinc will cause 

 injury even when used alone. As is well known, the same holds true 

 of Bordeaux mixture. In none of the cases of reported injury have we 



^ The nicotine determinations in these experiments were made by Mr. H. K. 

 McConnell, Assistant Chemist of The Kentucky Tobacco Product Co. 



