444 RECORD OF SCIENCE FOR 1887 AND 1888. 



By Blomstiand a remarkable series of platinum bases coutainiug; 

 organic radicles and sulphur are described. In one memoir he dis- 

 cusses the sulphin bases of methyl and ethyl, and in a second paper, 

 jointly with Eudelius aiul Londahl, the propyl, isopropyl, butyl, iso- 

 butyl, and benzyl bases are considered. The platoethylsulphin chloride, 

 Pt=(S(C2H5)2Cl)2, may be cited as a representative of these new com- 

 pounds. (Journ. Prakt. Chein. (2), xxxviii, 315 and 497.) 



Infiuence ofiinpurities upon gold. — Roberts- Austen, of the British mint, 

 investigating the influence of small impurities upon gold, attempts to 

 correlate his observations with the periodic law. Those metals whose 

 atomic volumes exceed that of gold, when alloyed with the latter ele- 

 ment, diminish its tenacity. Silver, having nearly the same atomic 

 volume as gold, hardly affects its toughness at all. So far as the ex- 

 periments go, tbe toughness of gold is not lessened by any element 

 which stands below it in Mejer's curve, while all the elements above 

 gold in the curve tend to make it brittle. (Berichte, xxr, ref. 508.) 



Salts of gold — In the periodic system gold may be placed with almost 

 equal propriety eitlier in line with the alkaline metals or in column 

 with the iron and platinum groups. Chemically, its relations suggest 

 the first-named grouping ; physically, it is nearer platinum. In a for- 

 mer paper Kriiss has shown that aurous oxide, like the alkalies, is com- 

 pletely soluble iu water, and now Hoffmann and Kriiss find a like state- 

 ment to hold good of aurous sulphide, which, when freshly prepared, 

 dissolves easily to a clear brown solution, from which it is precipitated 

 by hydrochloric acid and various salts. The trisulphide, AU2S3 ai)pears 

 not to exist, in spite of the common belief in its favor, but a sulphide, 

 AU2S2, is easily obtainable. The so-called trisulphide of chemical liter- 

 ature is a mixture of this auro auric salt Avitli free sulphur. (IJerichte, 

 XX, 2309 and 2704.) 



In experiments upon the halogen compounds of gold Kriiss and 

 Schmidt conclude that Thomsen's auro-auric salts, AU2CI4 and Au2Br4, 

 do not exist. When chlorine or bromine acts directly upon gold the 

 normal auric compound is produced. (Berichte, xx, 2634.) 



ORGANIC. 



Higher 2)araffins from broini coal. — In the oil distilled from brown coal 

 Krafift has identified a number of the higher homologues of methane. 

 Ee has isolated the members of the series from CnHge to C2:iH48 inclu- 

 sive, and finds them to be identical with the normal i)arattins prepared 

 synthetically. Seven of them are described in detail. (Berichte, xxi, 

 2250.) In other papers Krafft studies aromatic compounds involving 

 pentadecyl and hexadecyl groups, such as hexadecyl benzene, etc. {Ibid., 

 pp. 2205,3180.) 



The origin of petroleum. — Although petroleum is generally believed to 

 be of organic origin, some writers, and notably Mendelejeff, have sought 

 to show its derivation from inorganic material. Evidence as to its ani- 



