By M. W. SPRING.
The author has previously shown the possibility of uniting the
fragments of solid bodies by the sole action of pressure. He also
established at the same time the possibility of forming chemical
compounds by means of pressure. Thus he obtained cuprous sulphide by
compressing a mixture of sulphur dust and copper; mercuric iodide, by
compressing mercuric chloride with potassium iodide, etc. Finally, by
compressing in the same manner mixtures of the filings of different
metals, he formed alloys having for equal compositions the same melting
points as those obtained by fusion.
The last mentioned facts certainly establish the possibility of
causing bodies to enter into chemical reaction by the mere agency of a
mechanical energy. This result is closely linked with another obtained
during the course of the same investigation: the polymerization of
certain simple bodies, _e. g._, sulphur, by the action of pressure.
The author had drawn a general conclusion from his experiments, and
had announced that matter takes, below a given temperature, a state
corresponding to the volume which it is compelled to occupy.
He has since undertaken a methodical study of the chemical reactions
accomplished by the action of pressure. He had already shown the
possibility of forming metallic arsenides by compressing mixtures of
arsenic and of the filings of different metals (_Bulletin de l'Académie
Royale de Belgique_, t. v., 1883), and he now communicates the results
obtained by compressing mixtures of sulphur and of certain metals
or non-metals. The results not merely confirm the author's former
conclusions, but they throw a new light on the relations of organic and
inorganic chemistry, and exhibit the so-called simple bodies as capable
of assuming a peculiar constitution varying according to the conditions
in which they are placed, and the actions to which they are submitted.
He used the metals in the state of fine filings immediately mixed with
flowers of sulphur previously thoroughly washed. The mixtures were made
in atomic proportions and were submitted to a preliminary pressure of
6,500 atmospheres. They then assumed the state of a hard compact mass,
showing, on examination with the microscope, that the reaction of
the sulphur and the metal had taken place wherever the elements were
in contact. The mass obtained was then reduced into fine powder and
compressed again from twice to eight times.
1. _Sulphur and Magnesium._--After six compressions there was obtained
a gray mass with a feebly metallic surface luster. It dissolves in
water at 50° to 60° with a slow escape of hydrogen sulphide, the
liquid becoming of a golden yellow. A drop of hydrochloric acid
occasions immediately a very strong escape of hydrogen sulphide, while
free sulphur is deposited. Hence magnesium and sulphur combine under
the action of pressure, forming magnesium sulphide and possibly a
polysulphide.
2. _Sulphur and Zinc._--Three compressions yield a block deceptively
similar to native blende with metallic luster. Dilute sulphuric acid
dissolves the block slowly with an escape of hydrogen sulphide.
3. _Sulphur and Iron._--After four compressions a block is obtained
which the file scarcely touches. Dilute sulphuric acid dissolves it
easily with continuous escape of hydrogen sulphide. If the product
of compression is heated in a closed tube no luminous phenomenon is
observed, the body entering into tranquil fusion. Hence the potential
heat of the free sulphur and iron has been realized during the
compression.
4. _Sulphur and Cadmium._--Three compressions give a yellowish-gray
homogeneous mass. The powder is yellow, but less pure than that of
cadmium sulphide obtained by precipitation. Strong hydrochloric acid
dissolves the mass with escape of hydrogen sulphide.
5. _Sulphur and Aluminum._--Result incomplete. After five compressions
a mass is obtained which, in contact with moist air, gives off an odor
of hydrogen polysulphide.