February, '10] WOGLUM : SODIUM CYANIDE 87 



gen present in the sample as equivalent to 1, li/4 and 1% of the reg- 

 ular Schedule I for potassium cyanide as given in Bulletin 79, United 

 States Bureau of Entomology. The results of these experiments show 

 that not only is the effect on the insects as destructive as with equal 

 strengths of potassium cyanide, but rather more so. "Whereas it re- 

 quired a 1% schedule of potassium cyanide for eradication, a I14 

 schedule of the sodium produced the same result. This would signify 

 that under the crude conditions of orchard work a high grade sodium 

 cyanide gives a better generation of gas than a high grade potassium. 



For the sodium cyanide two parts of water were shown to be best 

 in the laboratory tests, whereas in the earlier field work referred to 

 three parts were used. The greater production of gas from two parts 

 of water over three parts, called for in the dosage schedules for the 

 potassium salt, is probably one of the reasons for the superior field 

 results later obtained from the sodium salt. 



Other experiments with a high grade sodium cyanide have been per- 

 formed. The results of these, so far as examined, have shown the 

 sodium to be at least equally efficient with the potassium. 



Effect of Sodium Chloride on the Production of Hydrocyanic- 

 Acid Gas. Newell in 1905 pointed out that sodium chloride, when 

 present in the reaction producing hydrocyanic-acid gas, results in a 

 partial decomposition of that gas. In order to ascertain more thor- 

 oughly the status of this salt, a large amount of experimental work has 

 been carried out. These tests not only corroborated Newell 's results, 

 but also showed that if a sufficiently large percentage of sodium chlo- 

 ride was present the decomposition would be so great as to result in the 

 liberation of little, if any, cyanide gas. The practical value of this 

 consideration is that all commercial cyanides contain more or less 

 sodium chloride. Analysis of a sample of the brand of sodium cyanide 

 formerly used in California orchard fumigation showed it to contain 

 14.2 per cent sodium chloride. The amount of cyanogen present was 

 101 per cent. While a 97 per cent commercial potassium cyanide, 

 containing only a trace of sodium chloride, yielded 94 per cent of its 

 total gas, this 101 per cent sodium cyanide yielded only 63 per cent 

 of its total, 34 per cent being decomposed, due to the presence of the 

 chloride. Other brands of 98-100 per cent sodium cyanide submitted 

 were shown to contain proportionately larger amounts of sodium 

 chloride. 



The presence of sodium chloride accounts for the failure of these 

 cyanides in past fumigation work. 



