I04 The Ohio Naturalist. [Vol. VII, No. 5, 



Chemicals used: In all tests the 1.1.3. formula was used: i. e., 

 1 oz. potassium cyanide, 1 fluid oz. sulfuric acid, 3 fluid oz. of 

 water. The cyanide was manufactured by Messrs. Merck & 

 Company, of New York, and was 99% pure, and an excellent 

 grade of commercial sulfuric acid was used. 



The table gives the results obtained: 



Experiments conducted by Prof. Wilmon Newell in Georgia 

 (Bulletin No. 15, Georgia State Board of Entomology) showed 

 that the violence of the reaction between the cyanide and diluted 

 sulfuric acid subsided at the end of five minutes, and that no gas 

 was evolved after ten minutes, if the cyanide was added so as to 

 be well covered with the liquid. 



From the data given in the table it appears that the gas first 

 evolved is driven to the top of the box by the violence of the 

 reaction, and that it passes in waves to the end farthest from the 

 jar. It then seems to gradually permeate the lower parts of the 

 box until thoroughly diffused, but the reactions are less marked 

 in samples taken from the upper hole at the greatest distance 

 from the jar after the box has been closed from thirty to forty 

 minutes. 



Results; Tests one and two which were made under normal 

 conditions, the box being dry, showed that the gas was well 

 diffused throughout the box at the end of forty minutes. The 

 poorest results in both tests were shown at hole D at the end of 

 the box opposite the jar. The sample taken three minutes after 

 the charge was "fired" showed a good precipitate, and the 

 amount of precipitate diminished as the time was lengthened. 

 The test at hole E, which was at the same end of the box but 

 several inches lower that hole D, gaA-e an excellent precipitate. 



In tests three and four, where the floor of the box was cov- 

 ered with water, practically the same results were secured, 

 although in test four the sample taken at hole D gave a good 

 precipitate. 



In test five the box was packed with stock and the temper- 

 ature was 72°. The results can hardly be considered con- 

 clusive, as the precipitate was allowed to stand in corked bottles 

 for twenty-three hours before it was tested. In nearly every 

 case, however, the samples showed a better precipitate the 

 longer the time elapsed before the sample was taken. 



Test six showed very similar results, although the box was 

 placed out of doors where the thermometer stood 32°. 



In test seven, where the stock was drenched with water, the 

 results were much less satisfactory. A trace of gas was detected 

 in each sample, and in a few slightly better results were noted. 

 The precipitates secured in the test were allowed to stand 

 seventeen hours and the condition is noted in the column adjoin- 

 ing test seven. • It will be noted that enough of the precipitate 



