February, '22] 



HEADLEE: CONTACT DUSTS 



79 



Table III. — Table Showing Effect on M. solanifolii of Increasing Nicotine Strengths anu 

 OF Increasing the CaO Used on Tomatoes 



Improvement in nicotine delivered as a dust m.ust apparently be 

 sought not in the direction of increasing nicotine percentages but in 

 better utilization of the 2% or less which comes within the range of 

 reasonable practice. With this point in view the determination of the 

 rate and amount of nicotine delivered from different carriers was under- 

 taken. Ten grams of each of the nicotine impregnated dusts were 

 placed in a glass container and a stream of air conditioned to 80° F and 

 73% relative humidity drawn through the dust at the rate of one liter 

 per minute. The results of this work, insofar as the work was complete 

 at the time of the preparation of this paper are set forth in table No. 

 4. 



Examination of this table will serve to show the mixtures giving off 

 nicotine in an ascending series as follows; — 



