MISCELLANEOUS SOLID INSECTICIDES AND FUNGICIDES. 47 

 ANALYSES AND DISCUSSION. 



Table IX gives the results obtained by the above methods of analy- 

 sis on four samples: 



9 



TABLE IX. Composition of tobacco extracts. 



flSee correspondence with manufacturers, uage 62. i 



I) The following formula for this substance is placed on the bottle: 37 per cent nicotine, 23 per cent 



camphor, 32 per cent pure alcohol, remainder, other essential ingredients. See correspondence with 



manufacturers, page 60. 



Both samples 19687 and 22288 contain very small quantities of nico-' 

 tine, and are consequently not good tobacco extracts. Sample 22289, 

 containing 26.01 per cent nicotine, is a good tobacco extract. Although 

 sample 2 I & W has not as much nicotine and camphor as are given 

 in the formula on the bottle, as an insecticide it will be apt to give 

 good results in actual practice. 



MISCELLANEOUS SOLID INSECTICIDES AND FUNGICIDES. 



The methods of analysis of the compounds under this heading are 

 given in only a few cases, because they are so numerous and because 

 most of them would immediately occur to anyone with a chemical 

 training. 



V 



METHODS OF ANALYSIS AND COMPOSITION OF COMPOUNDS. 

 BUG DEATH. 



[Serial No. 19555.] 



Method of analysis. The moisture determination is made by drying 

 the substance for 12 hours at 100 to 105 C. The residue is heated 

 to dull redness for volatile matter. For all of the other constituents 

 2 grams is dissolved in aqua regia by prolonged boiling. What remains 

 is weighed as sand. The filtrate from this is made to 250 cc and one- 

 hulf taken for analysis, about 3 or 4 cc of concentrated sulphuric acid 

 are added, and the solution evaporated until white fumes come oft' and 

 no odor of nitric or hydrochloric acid remains. It is diluted with 

 water, filtered, washed with water containing a little sulphuric acid, 

 and finall} 7 with 60 per cent alcohol. The lead sulphate thus obtained 

 is burned and weighed with the usual precautions. Sodium carbonate is 



