Elements of chemistry, in two volumes / by John Murray.

  • Murray, John.
Date:
1828
Catalogue details

Licence: Public Domain Mark

Credit: Elements of chemistry, in two volumes / by John Murray. Source: Wellcome Collection.

    21/768 (page 9)
    side of a galvanic battery, or, according to the method of Berzelius and Pontin, it may be placed in contact with a solution of pure ammonia in a platina spoon. On esta- blishing the contact with a wire from the negative side, the quicksilver begins to increase in volume; it thickens and becomes less mobile, and at length is enlarged to four or five times its original volume, and becomes a soft solid, retaining the metallic lustre: oxygen is at the same time evolved at the positive wire. The changes the quicksilver thus suffers are similar to what would be produced fiom the communication to it of metallic matter. Hence it was concluded, that in the experiment the ammonia suffers decomposition, probably by the abstraction of oxygen, and that its supposed metallic base, (Ammonium as it was named,) remains in combination with the quicksilver. This appeared to be confirmed by the fact, that when the ammoniacal amalgam, as this soft solid has been named, is dropt into water, it is resolved into quicksilver and am- monia, hydrogen gas being evolved, which was supposed to indicate a decomposition of water, and the transfer of its oxygen to the ammonium, so as to reproduce ammo- nia. This amalgam, at a temperature of 32°, acquires considerable hardness, and even crystallizes in distinct and regular cubes. The theory of this singular experiment has now been elucidated. Gay-Lussac and Thenard have shewn that this soft metallic solid is a compound of quicksilver with portions of ammonia and hydrogen, or an ammoniacal hydruret of mercury. In its production, the water with which the ammoniacal salt is moistened, and the presence of which is essential to the success of the experiment, is decomposed : its oxygen is attracted to the positive gal- vanic pole, while the hydrogen of the decomposed water, and a portion of the ammonia attracted to the negative