On a new fulminating mercury / By Edward Howard, Esq. F.R.S. From the Philosophical transactions.

  • Howard, Edward, 1774-1816.
Date:
1800
Catalogue details

Licence: Public Domain Mark

Credit: On a new fulminating mercury / By Edward Howard, Esq. F.R.S. From the Philosophical transactions. Source: Wellcome Collection.

    6/42 (page 4)
    that a strong electrical shock, generally acts on fulminating substances like the blow of a hammer. Messrs. Fourcroy and Vauquelin found this to be the case with all their mixtures of oxymuriate of potash.* To ascertain at what temperature the mercurial powder explodes, 2 or 3 grains of it were floated on oil, in a capsule of leaf tin; the bulb of a Fahrenheit’s thermometer was made just to touch the surface of the oil, which was then gradually heated till the powder exploded, as the mercury of the thermo¬ meter reached the 368th degree. SECTION IV\ Desirous of comparing the strength of the mercurial com¬ pound with that of gunpowder, I made the following experi¬ ment, in the presence of my friend Mr. Arernethy. Finding that the powder could be fired by flint and steel, without a disagreeable noise, a common gunpowder proof, capable of containing eleven grains of fine gunpowder, was filled with it, and fired in the usual way : the report was sharp, but not loud. The person who held the instrument in his hand felt no recoil; but the explosion laid open the upper part of the barrel, nearly from the touch-hole to the muzzle, and struck off the hand of the register, the surface of which was evenly indented, to the depth of 0,1 of an inch, as if it had received the impression of a punch. The instrument used in this experiment being familiarly known, it is therefore scarcely necessary to describe it; suffice it to say, that it was of brass, mounted with a spring register, * Annates de Cbimie, Tom. XXI. p. 239.