Chemistry and Physics. 81 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. The fiisibility of platinum in a blast-furnace fed by carbon, 

 — The oft-repeated assertion that platinum can be fused in a 

 furnace fed with carbon and air has been subject to some doubt 

 on account of the possibility of the contamination of the metal 

 by carbon or other substances in the furnace. Victor Meter 

 has now succeeded in melting the metal when enclosed in a thick 

 block of refractory earth in such a manner that no impurities 

 were taken up. The fuel used was retort carbon broken up in 

 pieces of the size of a hazel-nut, and the air was supplied by a 

 powerful blast. An alloy of 75 parts of platinum and 25 parts 

 of iridium, exposed to the same temperature in another cavity of 

 the same block of refractory material, remained entirely unaf- 

 fected. — Chem. Neics, Ixxiii, 235. h. l. w. 



2. The condition of the water in analcite.— In making an analy- 

 sis of analcite of peculiar form and optical properties Charles 

 Lepierre has taken occasion to determine the temperatures at 

 which the water is given off. He found that it lost almost exactly 

 half its water upon long heating to constant weight at 200°, and 

 that this loss was not increased at 300°. At 440°, however, all 

 of the remaining water was disengaged. The higher tempera- 

 tures, 300° and 440°, were obtained by the use of the vapors of 

 a high-boiling petroleum-product and of sulphur respectively, so 

 that these temperatures may be regarded as reliable. The 

 author believes that his results indicate that the formula repre- 

 senting the composition of the mineral is much simpler than that 

 proposed by F. W. Clarke, since according to the latter formula 

 the water would not be expected to be given off in two equal 

 parts. He proposes the formula H^Na^Al^Si^O^^, and develops it 

 in such a manner that four hydroxyl groups are attached to the 

 silicon atoms. — Bidl. /Soc. Chini., Ill, xv, 561. h. l. w. 



3. Quantitative separations by means of hydrogen peroxide. — 

 During the past five years Jannasch and his pupils have studied 

 a number of separations based upon the oxidizing action of hydro- 

 gen peroxide, usually in alkaline solution. The reactions utilized 

 are chiefly the precipitation of manganese, lead and bismuth as 

 peroxides, and the oxidation of chromium compounds to chro- 

 mates. The peroxides are precipitated in most cases by pouring 

 the moderately acid solution of the salts to be operated upon 

 into a mixture of an excess of ammonia and hydrogen peroxide 

 with continual stirring. In the case of lead and bismuth the opera- 

 tion is performed in the cold, while with manganese the whole is 

 warmed for a short time to cause the precipitate to settle. Sepa- 

 rations are thus made from zinc, nickel, cadmium, mercury, silver 

 and copper. In the separations from arsenic sodium hydroxide is 

 used in place of ammonia, and in some instances the separation is 



Ajt. Jour. Sci. — Fourth Series, Vol. II, No. 7. — July, 1896. 

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