THE DETECTION OF SMALL QUANTITIES OF 
MERCURY IN EXPLOSIVES. 
J. BROWNLIE HENDERSON, F.I1.C. and P. W. 
JONES, A.I.C. 
A Paper read before the Royal Society of Queensland, 
27th June, 1907. 
CONSIDERABLE trouble has arisen recently through the 
use of mercuric chloride by certain manufacturers in making 
up explosives, and this addition as is well-known masks the 
Abel Heat Test. 
So far as we have heard in Brisbane, both from pub- 
lished accounts and from private sources, no satisfactory 
chemical method of detecting the small quantities of mercury 
present in the explosives has yet been discovered, and in 
some prosecutions in London for the presence of mercury 
in explosives, the Government witnesses, including among 
others, Dr. Dupre and Sir Wm. Ramsay, relied solely on 
the spectroscopic method for the detection of mercury. 
In communicating with Mr. W. A. Hargreaves, Government 
Analyst of South Australia, on this subject, he informs us 
that the following method has been found to work well 
qualitatively in his Laboratory : 100 grammes of the explosive 
was ground up with 100 grammes of french chalk and 
heated in a flask in a water oven. Air was drawn through 
the flask gently for two hours, and then passed through 
dilute sulphuric acid to absorb the mercuric chloride vola- 
tilised. This acid was subjected to electrolysis, using a 
gold cathode and platinum anode. The gold was then dried 
and heated in a small combustion tube and the mercury 
_volatilised on to a microscope slide and examined under 
the microscope. We had succeeded in detecting traces 
of mercury by one or two rather long and unsatisfactory 
wet methods, but on getting this information from Mr. 
