Note 1584 — AURUM FULMINANS.

[That this and other similar chemical phænomena may be of more advantage than as affording merely subjects for speculation to the philosopher, although not immediately applicable to any useful purpose, may be inferred from the valuable application of fulminating mercury, a somewhat similar compound to that under consideration. This, at first, as with fulminating gold at present, was a mere curiosity; it has recently caused the almost complete substitution of percussion for flint locks in fire-arms, which in addition to the greater certainty caused by the increased rapidity of the discharge, œconomises the quantity of powder requisite.

Fulminating mercury is made by dissolving mercury in nitric acid and pouring the solution into warm alcohol. Effervescence ensues. When this has ceased, the mixture is poured upon a filter, and well-washed with water; after draining, the filter is expanded upon plated copper or stone-ware, heated to 212° by steam or hot water. Dr. Ure recommends that the powder be mixed with a solution of mastic in spirits of turpentine, to cause attachment. Its extensive use in making percussion-caps is well-known. It is however a very dangerous substance to experiment with, owing to the readiness with which it explodes, and has caused many very serious accidents.]