PROPORTION OF CHEMICALS. 
aiderable exceee of sulphuric acid present, h La perfectly possible, however, thai 
this excess of Bulphuric acid is of value in heating up the mixture bo thai more of the 
hydrocyanic acid is Liberated and uot absorbed bj the liquid. 
The results of some tests serve as a further illustration of this 
point. It was desired to determine by experiment if l fluid ounce of 
acid to each ounce (avoirdupois) of eyanid would be sufficient to 
carry the reaction to completion in the liberation of hydrocyanic- 
acid gas. It is to be understood throughout that the eyanid ounce 
is avoirdupois and the acid and water is the fluid ounce. For this 
test two series of ordinary lj-gallon Fumigating vessels were placed 
in line. In one series equal parts of acid and eyanid were used. 
Three parts of water were used in all cases. The amounts of eyanid 
used ranged from 1 to 10 ounces, that is, in one generator were 
placed 1 ounce of eyanid, 1 ounce 4 of sulphuric acid, and 3 ounces of 
water; in the next of the same series, 2 ounces of eyanid. 2 ounces 
of sulphuric acid, and (> ounces of water, and so on in the same pro- 
portion up to 10 ounces. The second series was identical with the 
first except for the use of one-fourth more acid than eyanid. After 
generation had taken place for about out 1 and one-half hours an 
examination was made of the residue. In the first series, in which 
equal parts of acid and eyanid were used, the residue was in the 
form of a liquid. In the second series, in which 1£ ounces of acid to 
1 of eyanid were used, the residue in several pots had collected in a 
mushlike mass. Being puzzled at first over this phenomenon, in 
order to ascertain if eyanid still remained unchanged in the residue 
the writer added more sulphuric acid, but there was no further evolu- 
tion of gas. This at once demonstrated that all the available eyanid 
had been dissolved. Analyses of this residue by J. K. Haywood of 
the Bureau of Chemistry showed that the reaction was complete both 
when 1 ounce of acid and when 1\ ounces of acid to 1 of eyanid were 
used. In submitting the result of these analyses, Dr. H. W. Wiley, 
Chief of the Bureau of Chemistry, wrote: 
The amount of eyanid present in these samples is so small that it does not indicate 
to us incompleteness of reaction, but rather indicates the amount of hydrocyanic acid 
dissolved in the residue. This view of the case is strengthened by the fact that 
increasing the amount of sulphuric acid in the cases above did not decrease the amount 
of cyanogen present in the residue. From our work, therefore, we are of the opinion 
that the same amount of sulphuric acid as of potassium eyanid is sufficient to carry 
the reaction to completion. 
" In an address printed in the Proceedings of the Thirty-fourth Annual Fruit Grow- 
ers' <onvention of California, p. 10:5, the proportion of chemicals spoken of appears 
somewhat different from that mentioned in this publication. This is due to the fact 
that the parts mentioned in that address were based on parts by weight of acid and 
eyanid, both of which are chemically pure — not the commercial product as given in 
this bulletin. 
77488— Bui. 79 09 3 
