Chemistry and Physics. 69 
sulphate soluble in water, with evolution of sulphurous oxide. It 
is not attacked by potassium hydrate. Its atomic weight, 
estimated by titering the chlorine contained in the tetrachloride, 
by the method of Volhard, was found to be 72°32 as a mean of 
four experiments. (Lecoq de Boisbaudran, it will be remembered, 
calculated the atomic weight from the two characteristic lines in 
its spectrum, A=468 and A=422°6, and found it to be 72°31 and 
72:27, by two different methods, (C. &., cii, 1291)). The position 
of germanium is that of the ekasilicium in Mendelejeft’s table, for 
which he predicted an atomic weight of 72 and a specific gravity 
of 5°5. Its specific heat as determined by Nilson and Peterson, 
is at 100°, 0:0737 ; at 211°, 6°0772 5 at301°5°, 0:0768; and at 440° 
00747; the corresponding atomic heats being 5°33, 5:58, 5°55 and 
5°47 respectively. These temperatures are the boiling points of 
water, nitrobenzene, diphenylamine and sulphur. The specific 
heat of the dioxide is 071293 between 0° and 100°. The vapor 
density of GeCl, is 7°43 and that of the iodide 20:43. Its spark 
spectrum shows one line in the orange, one in the yellow, four in 
the violet and twelve in the green and blue. Its compounds are 
characterized by their solubility and volatility, but they do not 
color the Bunsen flame. Two oxides, GeO and GeO, are de- 
scribed; and the corresponding sulphides and chlorides. Also 
Gel,. The best test for germanium is the precipitation of the 
white sulphide GeS, upon the addition of mineral acids in excess 
to its solution in alkaline sulphides. This separation is so com- 
plete that it may be used quantitatively. For this purpose, the 
alkaline solution of germanium is mixed with ammonium sulphide, 
precipitated with dilute sulphuric acid in excess and saturated 
with hydrogen sulphide. After 12 hours standing, it is filtered 
off and washed, the precipitate is washed from the filter and ex- 
tracted with ammonia. ‘The ammoniacal solution, with the wash 
water are evaporated to dryness in a weighed porcelain dish, the 
main precipitate moistened with sulphuric acid added thereto and 
the excess of acid evaporated. After ignition the residue is 
treated with nitric acid, again ignited, digested with ammonia to 
remove the last trace of sulphuric acid, and the strongly ignited 
oxide weighed. To separate this metal from tin, arsenic and anti- 
mony, the author dilutes the solution to a definite volume, boils a 
measured portion with excess of normal sulphuric acid and deter- 
mines by titering back the excess of acid required to exactly 
neutralize the entire solution. This amount is then added, the 
solution allowed to stand 12 hours, the precipitated sulphides are 
filtered off, the filtrate is evaporated to a considerably smaller 
volume, treated with ammonia and ammonium sulphide and pre- 
cipitated by the addition of an excess of sulphuric acid and the 
passage of a current of hydrogen sulphide. This precipitates 
germanium sulphide pure. Argyrodite, in which this element was 
discovered contains Ag 74°72, Ge 6°93, 8 17:18, Fe 0°66, Zn 0:22 
and Hg 0°31 per cent. It is a sulpho salt of the formula (Ag,S), 
GeS,.— J. pr. Ch., Il, xxxiv, 177-229; Ber. Berl. Chem. Ges., 
xix, 652 (Ref.) Nov. 1886. | Go EB: 
