CHEMISTRY. 223 



snrrounded by a series of fine, radiating cracks, which are the 

 result of the contraction suffered b\' the diamond in solidifying 

 over the inclosed crystal, and this explanation is verified b}' oo- 

 sei-vins: crystals formed in fused o'lobules of borax o^Jass cooled 

 slowly, where the same phenomenon is seen. — Chem, Neivs. 



MOLYBDENUM AND CHROMIUM. 



These metals can, according to Loughlin, be easily prepared 

 as follows : A mixture of one part of pure molybdic acid and 

 one and a half parts of c^yanide of potassium is placed in a porce- 

 lain crucible and the lid luted on ; this is placed in a large cruci- 

 ble and the interstices packed with animal charcoal. The en- 

 tire apparatus is then exposed to a strong white heat for 12 

 hours ; when cold the inner crucible is found lined with a white, 

 silver-like metal, not acted upon by hydrochloric acid, but readily 

 dissolved by nitric acid, and having a specific gravity of 8.56. 

 By substituting oxide of chromium for molybdic acid, metallic 

 chromium is obtained. — Engineer, 



MINERAL CAOUTCHOUC. 



Recent communications from Adelaide, South Australia, have 

 made known the discovery in the southern portion of the colony 

 of a remarkable carboniferous substance, which hitherto has only 

 been found in small quantity in the coal strata of Derbyshire 

 (England). It is a mineral caoutchouc, so called from its gQn-^ 

 ^ral appearance and elasticity. In Australia it is found on the' 

 surface of the sandy soil, through which it would appear to 

 exude from beneath, as, burnt otf occasionally by the bush fires, 

 it is again found after the winter season, occurring in quantity 

 and of varying thickness. Analysis i)roves it to yield 82 per cent, 

 or more of a pure hydrocarbon oil ; its value for the manufacture 

 of gas there will be great, and it is also believed to be applica- 

 ble to the making of certain djes. The discovery is also irajDor- 

 tant from its indication of the existence of oils or other carbonifer- 

 ous deposits. This material, known in mineralogy as elaterite, 

 is also found in a coal-pit at Montrelais, near Nantes, France, at 

 Neufchatel, and on the island of Zante. According to the analy- 

 sis of the late Professor Johnston, of Durlianl University, it is a 

 hydrocarbon, containing from 83.7 to 85.5 per cent, of carbon, 

 and from 12.5 to 13.28 per cent, of hydrogen. The variety found 

 in Derbyshire (near Castleton) has a specific gravity varying 

 between 0.9053 and 1.233 ; the substance is highly inflammable, 

 its color blackish bi'own, its lustre resinous. — Chem. News, 



SUMMARY OF CHEMICAL NOVELTIES. 



Decomposition of Alkaline Chlorides. — According to Messrs. 

 Kuentz and Jossinet, the decomposition of alkaline chlorides 



