492 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 16 
present is insufficient to free the alkaloid. Since we have no method 
of determining easily when the alkaloid is completely freed, the safest 
plan is to add a slight excess of alkali. If calcium caseinate is used as a 
spreader, it might be possible to reduce the amount of alkali added, 
but since many waters contain considerable quantities of carbonates 
or other lime-precipitating chemicals too much dependence should not 
be placed on the excess alkali in casein spreaders. 
Nicotine Dusts 
The use of dust carriers for nicotine instead of water, as developed by 
Professor R. E. Smith, has been a great advantage in certain types of 
work but with it have come some complicated problems. This is due 
to three reasons: first, the dilutant is at present sold with the nicotine 
Table III. Volatility of Nicotine in Various Dust Carriers. 3 
No. 
Form of Nicotine 
Carrier 
Time of 
Exposure 
Pet. of 
Nicotine 
Recovered 
Substance 
Proportion 
1 
Free nicotine 
Hydrated lime 
Sulfur 
per cent 
74.7 
24.2 
Hours 
18 
22.3 
2 
Free nicotine 
Hydrated lime 
Sulfur 
49.5 
49.5 
18 
25.3 
3 
Free nicotine 
Hydrated lime 
Sulfur 
87.8 
11.2 
18 
32.1 
4 
Free nicotine 
Hydrated lime 
Sulfur 
11.2 
87.8 
18 
trace 
5 
Free nicotine 
Sulfur 
99.0 
18 
none 
6 
Free nicotine 
Hydrated lime 
99.0 
18 
45.7 
7 
Free nicotine 
Sodium carbonate 
99.0 
18 
none 
8 
Free nicotine 
Kaolin 
99.0 
18 
96.3 
9 
Free nicotine 
Hydrated lime 
Water 
94.95 
4.05 
18 
54.6 
10 
Nicotine sulfate 
Kaolin 
97.5 
18 
100.0 
11 
Nicotine sulfate 
Hydrated lime 
97.5 
18 
25.1 
12 
Nicotine sulfate 
Sodium carbonate 
97.5 
18 
none 
13 
Nicotine sulfate 
Ammonium carbonate 
97.5 
18 
none 
14 
Nicotine sulfate 
Hydrated lime 
Sodium carbonate 
48.7 
48.7 
18 
trace 
3 Temperature range 58° to 70° F. 
