A Comprehensive Treatise on Inorganic and Theoretical Chemistry

174 INORGANIC AND THEORETICAL, CHEMISTRY
observed that in some infectious maladies, the colloid promoted oxidation of the
tissues, and the cure of the disease. C. Levaditi and co-workers found the double
thiosulphate of platinum and sodium to be less active than the corresponding
salt of gold in its trypanocidal action on rabbits.
Compact platinum was found by H. Thiele and K. Wolf to have no baneful
action on bacteria. E. Behring, JIi. Bitter, E. Rosenthal and W. Bamberger, and
the Farbwerke vorm. Meister, Lucius und Bruning studied the value of platinum
salts as antiseptics ; A. Calmette, A. Pedler, and T. L. Brunton and J. Fayrer, as
antidotes for snake poisoning. H. Micheels and P. de Heen, the favourable action
on the germination of wheat ; A. Chassevant and C. Richet, the inhibiting action
on the lactic fermentation of whey ; A. Devaux, the non-fixation of platinum by
the cell walls of plant stems from which the calcium and magnesium salts have
been abstracted by acids ; and T. Thunberg, the null-effect of hydrochloroplatinic
acid on the absorption of oxygen by lecithin.
Some uses of platinum.—C. Ridolfi 26 tried plating copper and brass with
platinum leaf to make stills and evaporating pans, but not successfully. Platinum
plating gives a non-tarnishable coating for silver and base metals. Platinum
generally alloyed with 10 per cent, of iridium has been employed in making standard
international measures of length, and weight ; the metal is employed in the production
of mirrors, and cross-wires for optical instruments ; and in the construction
of pyrometers—e.g. thermo-couple, contact breakers and resistance pyrometers,
as well as optical pyrometers. The metal is used in the construction of chemical
apparatus—e.g. crucibles, gooch filters, electrodes, etc. K. Falck described the
use of platinum in dental work as alloys and pins for artificial teeth, foil for crowns,
and supports for dentures ; in electro-analytical work, a catalyst in numerous
chemical reactions—the oxidation of ammonia, and of sulphur dioxide—and in
the construction of automatic gas-lighters ; in the electrical industries for glassto-metal
joints, and for various contacts particularly if arcing is liable to occur.
Platinum or platinum-iridium points are used for hypodermic syringes, and for
cautery points. Platinum or a gold-platinum alloy is used in the artificial silk
industry for spinnerets ; and for spraying jets in the manufacture of sulphuric
acid. Platinum and its alloys are used as a non-magnetic substitute for steel in
some chronometers and watches. It has been tried in the construction of incandescent
lamps, as a resistance material in the construction of electrically heated
muffles, as platinum points in magnetos for aeroplane motors, etc. Investigations
are being made of platinum-iridium flutes which are said to have a greater purity
of tone than flutes made of other materials. The salts of platinum are also
employed as reagents—e.g. in the determination of potassium, rubidium, and
caesium—and in photographic work—e.g. in platinum printing, and toning.
According to B. N. Menschutkin, in 1828, the Russian Government had accumulated
large stores of platinum from the Uralian districts, and the metal was minted
as coins of 3, 6, and 12 roubles. This was continued until 1845, when the minting
was stopped and the coins withdrawn from circulation, the reason being that
the Russian Government was unable to fix and maintain the price of the metal,
so that large quantities of coins passed to other countries. Some platinum medals
have also been struck. Platinum is also employed in jewellery.
REFEKKNCKS.
1 E. C. C. BaIy, Proc. Boy. Soc., 72. 84, 1903 ; Phil. Trans., 202. A, 183, 1903 ; Phys. Zeit.,
4. 799, 1903; B. Brauner, Chem. Netus, 71. 116, 1895; J. N. Collie, Proc. Boy. Soc., »7. A,
349, 1920 ; W. T. Cooke, ib., 77. A, 148, 1906 ; Zeit. phys. Ghent., 55. 537, 1906 ; H. Damianovich,
Anal. Inst. Investigation Cient. Tech., 1. 30, 1930 ; 2. 15, 24, 1931 ; Anal. Pis. Quim., 26. 365,
1928 ; Anal. Soc. Cient. Santa Pe, 6. 17, 20, 1934 ; Anal. Soc. Cient. Argentina, 118. 227, 1934 ;
Anal. Assoc. Quim. Argentina, 17. 95, 1929 ; Qazz. Chim. Ital., 59. 571, 1929 ; Compt. Bend.,
188. 79O, 991, 1929 ; H. Damianovich and Q, Berrez, Anal. Inst. Investigation Cient. Tech., 1.
58, 1930 ; H. Damianovich and J. Piazza, ib., 1. 45, 59, 1932 ; 2. 15, 24, 1933 ; H. Damianovich
and J. J. TriUat, Compt. Bend., 188. 991, 1929; J. M. Eder and E. Valenta, Sitzber.