An account of anew Fulminating Silver, and its application as a Test for Chlo- 
rine, Sc. By EDMUND DAVY, F.R.S., M.R.LA., &c., Professor of 
Chemistry to the Royal Dublin Society. 
Read May 23, 1831. 
I varecy had the honor of sending to the Royal Irish Academy, a paper of mine, “ On 
a new Acid and its Combinations,” published by the Royal Dublin Society. Whilst 
it was printing, I found that some of the compounds therein described, sponta- 
neously exploded when brought in contact with chlorine gas. Such unexpected re- 
sults appeared sufficiently interesting to merit further inquiry: accordingly, I insti- 
tuted a series of experiments on the subject ; and as they have led to a number of 
new facts which may admit of useful applications, I venture to submit some of them 
to the consideration of the Academy. In the present communication, | purpose to 
give a brief account of a new fulminating silver I have obtained, and of the principal 
experiments which illustrate its efficacy as a test for chlorine. 
1, Modes of making the new Fulminating Silver ; its properties and composition. 
This compound may be readily prepared from Howard’s well-known fulminating 
mercury by the following simple processes :—Put any quantity (suppose from ten to 
fifty grains or more,) of Howard’s compound, either in a dry or moist state, into a 
phial, with about half an ounce of pure water, and about twenty grains of zine filings, 
or granulated zinc, for every ten grains of Howard’s compound used. Cork the 
phial and occasionally agitate its contents, for about twenty or thirty minutes. Less 
time will answer if the water is moderately warm. ‘The fluid is fulminate of zinc ; 
filter and treat it with nitrate of silver, the white precipitate which occurs is the new 
fulminating silver. This substance may also be easily made, by adding nitrate of sil- 
ver to an aqueous solution of any of the soluble fulminates I have described in the 
paper already alluded to, or from Howard’s fulminating silver by the means recom- 
mended aboye, in the case of the fulminating mercury ; and after being collected on 
