470 Scientific Intelligence. 



not easy to prepare. Rubidium, though acted on by acetylene at 

 low temperatures, gives rise to no definite product. Zinc and mer- 

 cury are scarcely acted on, and iron, like copper, acts catalytically, 

 inducing condensation to oily hydrocarbons. Acetylene pro- 

 duces no precipitate in solutions of thallium, lead, cadmium, iron, 

 nickel, cobalt, platinum, iridium, and rhodium. Gold chloride 

 gives a black precipitate, changing to metallic gold on warming. 

 Palladium chloride gives a brown precipitate soluble in ammonia. 

 Copper acetate yields a brownish-red and silver nitrate a white 

 precipitate. By saturating a hot solution of mercuric nitrate with 

 acetylene, mercurocarbide nitrate HgC \ CHg. HgN0 3 . H 2 sepa- 

 rates in small white crystals. It yields acetaldehyde on treatment 

 with dilute acids. — -Zeitschr. anorg. Chem., xviii, 48-58, 1898. 



G. F. B. 



4. On JEhttropic Series of the Calcium Group. — In 1896 Linck 

 proposed the term catameric eutropy or more briefly eutropy, for 

 those special cases of isomorphism in which the geometrical and 

 physical characters of members of a series increase or decrease 

 regularly with increase of the atomic mass of the varying ele- 

 ment ; as is the case for example in the potassium, rubidium and 

 caesium compounds described by Tutton. Subsequently he called 

 attention to the fact that the quotients obtained by dividing the 

 crystal volumes of the different members of such a series by their 

 molecular volumes are in the ratio of simple natural numbers. 



These relations have been recently tested by Eppler, who 

 finds that they both hold good in the calcium-barium-strontium 

 group, with one or two exceptions, as in the case of the three 

 anhydrous sulphates, anhydrite, celestite and barite. In his paper 

 he has brought together and compared numerous data concerning 

 the crystallized compounds of this series of elements, giving new 

 geometrical, optical and density determinations. In the case of" 

 cubic crystals the volume is unity and the above mentioned quo- 

 tient is inversely proportional to the molecular volume. In the 

 cubic oxides, fluorides, chlorides and nitrates of calcium, stron- 

 tium and barium, the ratios are 11 : 15 : 19, 14 : 17 : 20, 18:19: 20,, 

 and 20 : 21 : 22 respectively; thus decreasing with the increase in 

 molecular mass. Although lead compounds are frequently iso- 

 morphous with those of calcium, strontium and barium, they do 

 not belong to the same eutropic series, the physical constants fall- 

 ing between those of calcium and strontium or before or after 

 those of the barium salt corresponding. — Zeitschr. Kryst. Min. r 

 xxx, 118-175 ; J. Chem. JSoc, lxxiv, 560, December, 1898. 



G. P. B. 



5. The distribution of Vanadium. — It was shown by Hassel- 

 berg in 1897 (Astrophys. Jour., vi), that the mineral rutile con- 

 tains vanadium in small but varying amount. He has now (ibid., 

 ix, 143) continued his investigation to a considerable number of 

 meteoric stones, and concludes from this that vanadium is always 

 present in them, although it has not been detected in meteoric 

 irons. A recent paper by Hillebrand (this Journal, vi, 209) has 



