OF POISONING WITH COPPER
Poisoning with the salts of copper was not long ago a common accident,
in consequence of the metal being much used in the fabrication of
vessels for culinary and other domestic purposes, or ignorantly resorted
to by confectioners and others to impart a good colour to sweetmeats and
preserves. Such accidents have been materially diminished in frequency
since the poisonous qualities of the metal, and the circumstances under
which it is acted on by articles of food, have become known.
Nevertheless they are still frequent enough. The diffusion among the
common people of the knowledge of the properties of copper has also
naturally led some persons to have recourse to its preparations for the
purpose of self-destruction. Poisoning with copper has seldom been
caused by the wilful act of another person; for the deep colour of its
compounds and their strong disagreeable taste render it a difficult
matter to administer them secretly. This, however, though difficult, is
not impossible: whatever may be swallowed accidentally, may be also
administered secretly. In 1795 a woman Inglis was tried at Aberdeen for
administering sulphate of copper with intent to poison; but the charge
was not proved.[1047] In 1842 an attempt was made at Béziers in France
to poison a young woman by dissolving this salt in her coffee; but the
first mouthful caused such a sense of constriction in the throat as to
apprize her of something deleterious being present, and she escaped
after suffering from soreness of the mouth, vomiting and cramps.[1048] A
case of imputed poisoning with sulphate of copper has been related at
page 76.
SECTION I.—_Of the Chemical History and Tests of the Preparations of
Copper._
Metallic copper has a special red colour, to which it gives its own
name. Its specific gravity is nearly 9, its hardness considerable, its
tenacity great, its point of fusion about 27° W. or at a full white
heat.
It unites with oxygen in two proportions, forming a yellowish-red
protoxide, and a peroxide, which, when dry, is brownish-black—when
hydrated, azure-blue. It unites also with sulphur in two corresponding
proportions, forming a gold-yellow proto-sulphuret, the natural
copper-pyrites, and a black bisulphuret, which is formed by
sulphuretted-hydrogen in all the solutions of this metal. The peroxide
unites with ammonia. The acids all unite with the oxide and form blue or
green salts, some of which are soluble, some insoluble. The oxide is
frequently mixed with other matters to form various pigments; but in
such compounds the union is generally mechanical, not chemical. Of the
substances thus formed and existing in nature and the arts the following
only require notice here. 1. _Mineral green_, and other pigments formed
with the hydrated oxide. 2. _Natural verdigris_, or the carbonate. 3.
_Blue vitriol_, or the sulphate. 4. _Artificial verdigris_, or the mixed
acetates.