Fulminating Bis′muth. Prep. From bismuth, 120 parts; carburetted cream of tartar, 60 parts; nitre, 1 part. Very rich in potassium.—Prop., &c., resemble those of the last. We have been assured that this is the compound used by the late Capt. Warner for some of his secret fusees.
Fulminating Cop′per. Syn. Fulminate of copper. Prep. Digest copper (in powder or filings) with fulminate of mercury or of silver, and a little water. It forms soluble green crystals that explode with a green flame.
Fulminating Gold. Prep. Recently precipitated peroxide of gold is digested in strong liquor of ammonia for 24 hours, and the resulting product is dried in the open air or at a temperature below 180° Fahr., care being taken to avoid the slightest friction, lest it should explode. A deep olive-coloured powder.
Obs. This compound can only be safely made in very small quantities at a time, as without great care it explodes with extreme violence. This is caused by the slightest friction or sudden increase of heat. Its fulminating property may be destroyed by boiling it in pearlash lye, or weak oil of vitriol; and by heating the residuum after washing it in water, pure gold will be obtained.
Fulminating Mer′cury. Syn. Fulminate, Fulminate of mercury. Prep. 1. Mercury, 1 part; nitric acid (sp. gr. 1·375), 12 parts; dissolve, add at intervals, to this solution, alcohol (sp. gr. ·850), 16·3 parts; apply heat till the effervescence and cloud of gas disappears, adding, gradually, on the action becoming violent, 16·3 parts more of alcohol.—Product. 112% of the mercury employed.
2. Mercury, 100 parts; nitric acid (sp. gr. 1·4), 1000 parts (or 740 parts by measure); dissolve by a gentle heat, and when the solution has acquired the temperature of 130° Fahr., slowly pour it through a glass funnel tube into alcohol (sp. gr. ·830), 830 parts (or 1000 parts by measure); as soon as the effervescence is over, and white fumes cease to be evolved, filter through double paper, wash with cold water, and dry by steam (not hotter than 212°) or hot water. The fulminate is then to be packed in 100 gr. paper parcels, and these stored in a tight box or corked bottle.—Product, 130% of the weight of mercury employed.
Prop., &c. Small brownish-grey crystals, which sparkle in the sun; entirely soluble in 130 parts of boiling water, and deposited as the solution cools under the form of beautiful pearly spangles. It greatly resembles fulminate of silver in its appearance and general properties. It explodes violently by both friction and percussion, but unlike the silver-salt, merely burns with a sudden and almost noiseless flash when kindled in the open air.
Obs. The second formula is not only the cheapest, but the best and safest. The first is more expensive and dangerous. There is no little hazard in pouring the alcohol into the nitric solution; for at each effusion an explosive blast takes place; whereas, by pouring the solution into the alcohol, no danger whatever is incurred. This preparation is used for priming the copper percussion caps for fowling-pieces, muskets, &c. Dr Ure, in his first report to the Board of Ordnance, recommended the use of a spirituous solution of gum sandarac, as the best substance for diluting the fulminate, and fixing it in the caps; but in a subsequent report to the same Board, he stated that a solution of mastic in spirit was to be preferred. At the present time the following composition is applied to the interior of percussion caps in quantities varying from ·2 to ·3 of a grain:—Chlorate of potassium, 26 parts; nitre, 30; fulminate of mercury, 12; sulphur, 17; ground glass, 14; gum, 1, making altogether 100 parts. (Watts.)
Caution. Fulminate of mercury should only be dried in small parcels at a time, and these should be placed at a distance from each other. The dreadful explosion which occurred some years ago at Apothecaries’ Hall, and by which Mr Hennel, the talented chemist of the Apothecaries’
Company, lost his life, was occasioned by the spontaneous detonation of this substance.