December, ’23] 
CAMPBELL: NICOTINE DUST PROGRESS 
501 
the machine proceeds down the rows, the troughs prevent the escape of 
most of the dust. These troughs are especially useful in windy weather. 
Early in his work with nicotine dust, Professor Smith conceived the 
idea of a self-mixing duster, in which the nicotine solution and carrier 
could be mixed at the time of application. During the 1922 season 
such a machine was developed, being an adaptation of one of the regular 
dusters on the market. Early in 1923 two different firms began the 
manufacture of self-mixing dusters. Both of these have been tested, 
and while subject to some mechanical imperfect ions, as might be expected 
in new machines, the success of self-mixing dusters was demonstrated. 
The advantages of self-mixed dust are as follows: (1) The dust is much 
cheaper, being limited to the cost of raw products only; (2) it is perfectly 
fresh; (3) it is hot from the mixing and chemical reactions, and therefore 
more active; (4) there is no loss of nicotine from storage, and (5) it is 
possible to make quickly any strength desired. Of course, there still 
will be a large demand for the ready-made dusts, for use in the machines 
not suited for self-mixing, and in hand dusters. Many growers do not 
care to take the time and trouble of mixing their own materials, while 
others feel that with the type of labor available in some localities, the 
possibility of using the wrong dosage and improper mixing will be too 
great. The self-mixing dusters can be used for applying ready-made 
dusts, arsenate of lead, sulphur, or other necessary material. 
Considerable emphasis has been placed on the thoroughness of mixing 
nicotine dust, and many have doubted if the self-mixing machines 
would do this satisfactorily. Professor Smith recently tested this by 
placing 40 pounds of hydrated lime and 2 pounds of 40 per cent nicotine 
sulphate solution in the hopper and running the machine for two minutes. 
A sample was then taken from near the top and one from near the bottom 
of the hopper. The machine was then run 8 minutes and two more 
samples taken. These were analyzed by the California State Depart¬ 
ment of Agriculture and showed the following percentages of nicotine: 
1.88, 1.89, 1.88 and 1.87, thus definitely proving the evenness and 
thoroughness of the self-mixing operation. 1 
A later analysis gave the following results: 
*Data from personal correspondence. 
