Another fulminating compound with mercury, was dis covered by Air Howard. It is prepared, by dissolving grains of- mercury in one ounce and a half of nitric acid of the common strength. When the solution is cold, add to it two ounces of alcohol. Heat the mixture gradually till effervescence takes place. A greyish white precipi tate will now be formed, which must be separated by the fibre, washed with distilled water, and dried at a heat not exceeding 2129.
This powder fulminates with great violence. A few grains laid upon an an-•il, and sti uck with a hammer, gives a report as loud as a pistol. The same effect takes place, by triturating it in a mortar.
It produces a much greater quantity of light. than any other of the fulminating compounds, but vei y little heat. When it is mixed with gunpowder, and a train of the ful minating mercury be laid into the mixture, and fired by the lighted paper, the whole of the fulminating mercury will be consumed without firing the gunpowder.
Whether fulminating mercury be exploded by heat or by percussion, the surface of the bodies near to it become co-; vered with the vapour of mercury.
This compound is said to consist of the oxide of mercury, combined with oxalic acid, and a large quantity of nitrous etherized gas. The explosive effect is to be attributed to the oxygen of the mercury combining with hydrogen in the etherized gas.
The fulminating compound, composed of three parts ni tre, two parts potash, and one of sulphur, has been long known. When a little of this mixture is laid upon an iron shovel, and held over the fire, or placed upon burning coals, or even held over the flame of a candle, it first melts, and then very suddenly explodes with a report equal to that of a musket. Equal parts of sulphuret of potash and nitre form the most perfect compound. Hence it is evident, that during the melting of the first preparation, the sulphur unites with the potash, forming a sulphuret, which at the same moment acts upon the nitre. The explosive effects are to be attributed to the formation and rapid evolution of &dphureted hydrogen and sulphurous acid gases, the dis engagement of azotic gas, and the highly elastic steam from the water in the nitre and potash. (e. s.)