A Comprehensive Treatise on Inorganic and Theoretical Chemistry

PLATINUM 3
resembled the white metal found by Jf. A. Genth in some Calif ornian gold ores. The metal
was unnamed, and the reports unverified. S. Item reported the disco vex-y of a new element
in some platinum residues, and he named it davyum, but J. W. Mallet showed that davyum
is a mixture of iridium, rhodium, and iron. T. "WiIm reported a new element in platinum
ores, but he did not assign to it a name, and A. Guyard reported an element ourali'uyrh in
Russian platinum, but both reports are unconfirmed. A. del Campo y Cerdan and S. P. do
Rubies could detect no new element in the platiniferous minerals from the Urals.
In April, 1803, R. Chenevix 3 received an anonymous circular to the effect
that a new metal called palladium could be purchased at Forster's of Gerrard
Street, Soho, London. The new metal had these properties, amongst others,
which showed it to be a noble element previously unknown :
1. It dissolves in pure spirit of nitre, and makes a dark-red solution. 2. Green vitriol
throws it down in the state of a regulus from this solution, as it always does gold from
aqua regia. 3. If you evaporate the solution you get a red calx that dissolves in spirit
of salt or other acids. 4. It is thrown down by quicksilver, and by all the metals but gold,
platinum, and silver. /5. Its specific gravity by hammering was only 11*3 ; but by
flattening as much as 11-8. 6. In a common fire the face of it tarnishes-a little and turns
blue, but comes bright again, like other noble metals, on being stronger heated. 7. The
greatest heat of a blacksmith's fire 1 WOuId hardly melt it. 8. I3ut if you touch it whilo
hot with a small bit of sulphur, it runs as easily as zinc.
R. Chenevix believed this was a fraud ; he bought up the whole stock ; and,
after investigating the question, concluded that the substance was not a new
element, but rather a platinum-amalgam of peculiar properties. Following the
publication of II. Chenevix at the Royal Society, May 13, 1803, where
W. H. Wollaston was Secretary, there appeared an advertisement offering a reward
to any one who could prepare a grain of this new substance either by R. Chencvix's
method, or by any other. No one succeeded in securing the reward, and in 1804,
W. H. Wollaston announced that he himself was the discoverer of the new element
in platinum ore, and added that he selected the name palladium from the planet
Pallas discovered in 1802. It is now difficult to understand why the Secretary
allowed the communication of R. Chenevix to be recorded in the transactions of
the society. The work of W. H. Wollaston was confirmed by V. Rose and
A. F. Gehlen, L. N. Vauquelin, J. B. Trommsdorff, and J. J. Berzelius. The subject
was discussed by A. M. White and H. B. Friedman, N. I. StepanofT,*.R. K. Fritzman,
and M. R. Weeks.
When W. H. Wollaston announced that he was the discoverer of palladium, he
also intimated that he had found another new element in platinum ore, and had
given it the name rhodium—from /ooSov, a rose—in allusion to the fact that soln.
of the salts of the metal have a rose-red colour. The results were confirmed by
J. J. Berzelius, and C. Claus. In 1803, H. V. Collet-Descotils, and A. F. de Fourcroy
and IJ. N. Vauquelin announced the existence of two metals in that part of platinum
ore which is insoluble in aqua regia ; and in 1804, S. Tennant showed that the residues
contained two distinct metals, one was named iridium—from iris, the rainbow—on
account of the varying colours of its salts, and the other, osmium—from 6