36 



FUMIGATION INVESTIGATIONS IN CALIFORNIA. 



Table II. — Experiment to determine the effect of different proportions of water on the 

 temperature of the resulting gas. 



In this experiment 5 ounces (avoirdupois) of cyanic! and 5 ounces 

 (fluid) of acid were used for each test. The proportions of water were 

 varied, 5, 10, 15, 20, 25, 30, and 40 ounces, respectively, being used. 

 As a result the proportion of water to 1 part of acid or 1 part of cyanid 

 was 1, 2, 3, 4, 5, 6, and 8, respectively, for the different tests. These 

 generations were made in a H-gallon fumigating vessel in a room. 

 The temperature of the escaping gas was taken at the mouth of the 

 pot. The temperature of the acid-water mixture was taken one 

 minute after pouring the two together. The cyanid was then added. 



The maximum temperature of the escaping gas is always realized 

 within the first minute, usually thirty to forty seconds after the gener- 

 ation commences. Examination of the maximum temperature of the 

 gas as noted in the third column of the table above indicates that the 

 temperature of the gas is reduced when large proportions of water 

 are used. When using from 1 to 4 parts of water, the temperature 

 is nearly uniform, but with 5 parts of water the decrease becomes 

 marked. Repetitions of the above experiment gave similar results. 

 The violence of the reaction and the temperature of the gas are affected 

 more or less by the size of the pieces of cyanid. A very violent reac- 

 tion results from the use of cyanid in powdered form. 



We would expect that to increase the proportion of water would 

 decrease the temperature of the gas. One reason is shown in this 

 table under the column marked "Temperature of the acid and water 

 mixture." As the proportion of water to sulphuric acid becomes 

 larger the resulting temperature of the mixture is lessened. Hence 

 when the cyanid is added to the mixture as high a degree of heat to 

 start the reaction is not developed as when the smaller proportion of 

 water is used, and in consequence gas is evolved less violently. 



THE TEMPERATURE OF THE GAS WHERE LARGE AND SMALL DOSAGES ARE USED. 



In an experiment to determine the temperature of the gas result- 

 ing from large and small dosages (Table III) the chemicals were used 

 in the following proportions: Cyanid 1 part, acid 1 part, and water 



