102 



HYDROCYANIC-ACID GAS FUMIGATION IN CALIFORNIA. 



manipulation. The average amount decomposed is less than 2 per 

 cent and the average remaining in the residue is practically 3 per cent, 

 which shows that when operating with pure sodium cyanid and sul- 

 phuric acid we may expect to obtain close to 95 per cent of the theo- 

 retical yield of hydrocyanic-acid gas expelled and available for 

 fumigation purposes. Sodium cyanids were then prepared containing 

 varying quantities of sodium chlorid and the determinations made in 

 the same wav. The results are tabulated as follows: 



Experiment No. 



Equiva- 

 lent of 

 HCX in 

 sample. 



Sodium 

 chlorid 

 in sam- 

 ple. 



HCX 



evolved. 



6 



7 

 8 

 9 



10 



Per cent. 



Per cent. 



47.16 



9 



43.18 



16f 



34.55 



33§ 



25.91 



50 



17.27 



66§ 



Per cent. 



41.96 



27. 42 



H)! 57 



5.85 



1.27 



HCX re- 

 maining 

 in resi- 

 due. 



Per cent. 



0.66 



1.71 



.37 



.05 



.10 



HCX de- 

 com- 

 posed 



(b in'S er " 1 



Per cent of total HCX. 



Per cent. 

 4.54 

 14.05 

 23. 61 

 25.91 

 15.90 



In res- 

 idue. 



88.98 

 63.49 

 30.61 

 22.58 

 7.35 



1.40 



3.97 



1.06 



.21 



.63 



Decom- 

 posed. 



9.62 

 32.54 

 68.33 

 77.21 

 92. 09 



AMMONIA FORMED FROM THE DECOMPOSITION OF THE CYANID. 



The amount of ammonia, existing as ammonium sulphate, in the 

 residue in flask "A" and that passed over into "B" was determined 

 in several cases and the nitrogen calculated therefrom. These 

 amounts added to the calculated amount of nitrogen in the hydro- 

 cyanic acid recovered in "A" and "B" correspond almost exactly 

 with the theoretical amount of nitrogen in the quantity of cyanid 

 employed. The distribution of nitrogen was as follows: 



Distribution of nitrogen in the residue. 



Determination. 



Experi- 

 ment 7. 



Experi- 

 ment 8. 



Experi- 

 ment 9. 



In "A": 



Xitrogen as cyanid. . 

 Xitrogen as ammonia 

 In"B": 



Xitrogen as cyanid . . . 

 Xitrogen as ammonia 



Per cent. 



0.79 



49.84 



46.83 

 2.54 



Per cent. 



1.05 



66.82 



30.40 

 1.73 



Per cent. 



0.21 



73.11 



23:23 

 3.45 



This shows that one of the principal decomposition products is 

 ammonia, the greater part of which is held in solution in the generating 

 flask by the excess of sulphuric acid as ammonium sulphate. 



Experiments carried out on the samples of commercial cyanids, 

 the analyses of which are given on page 92, gave the following results: 



