AURUM Fulminans

, a preparation from gold, which being thrown into the fire, it explodes with a violent noise, like thunder. The matter is produced by dissolving gold in aqua regia, and precipitating the solution by oil of tartar per deliquium, or volatile spirit of sal ammoniac. The powder being washed in warm water, and dried to the consistence of a paste, is afterwards formed into small grains of the size of hempseed.

It is inflammable, not only by fire, but also by a gentle warmth; and gives a report much louder than that of gunpowder. A single grain laid on the point of a knife, and lighted at a candle, explodes with a greater report than a musquet: and a scruple of this powder, it is said, acts more loudly than half a pound of gunpowder; and yet it is said that, by mixture, it does not increase the elastic force of sired gunpowder. Dr. Black attributes the increase of weight, and also the explosive property of this powder, to adhering fixable air.—This is a very dangerous preparation, and should be used with great caution.