Chemistry ond Physics. 411 
ing to which the so-called valence of the elements or their position 
in the system, is determined. Only after the production of the 
oxide forming the highest salts, can the element yield a peroxide 
of the type of hydrogen peroxide. There is no ground for the, 
assumption that hydrogen, barium, ete., can give still higher stages 
of oxidation, and then perhaps yield acidic oxides. Sulphur per- 
oxide confirms this view completely and leads to the expectation 
of the discovery of similar peculiar peroxides with many of the 
other elements.— Ber. Berl. Chem. Ges., xv, 242, Feb., ory 
a 
On the ee and “oli aaponed of metallic inet 
12 to 14 hours. The mother liquid contained no trace of cesium 
or rubidium salts but the crystals were rich in these metals; the 
author having found that each of the different alums is insoluble 
in saturated solutions of the more soluble ones. Hence o long as 
the solution of the alums was saturated with kone alum i 
contained scarcely a trace of the other alums; and the solution 
showed no trace of cxsium, so long as it was ‘saturated with ru- 
bidium alum. By repeating this process the alums were obtained 
ure. Search for other alkali-metals gave a negative result. In 
a Setterberg prepared . ies: ams rubidium alum and 10 
rams cesium alum both At 17° C. 100 parts of water 
diast ed 1°42 parts of mabidiedy alum and 0°38 parts of cesium 
alum. For the preparation of other salts, the sion were decom- 
posed with barium hydrate, and the filtrate neutralized with the 
: oe mene y the acid ta 
the cyanides were prepared. or the preparation of metallic 
rubidium, 1500 grams hydrogen-rabidium tartrate, 150 grams eal- 
Gockroly ds method was then employed first with the chloride and 
then with the cyanide of ceesinm. Finally a mixture of 4 molecules 
cesium cyanide and one of barium cyanide was found to give 
a satisfactory result, the metal prepared showing in the spectro- 
scope only a tra of sodium as an impurity. Cesium resembles 
closely the other alkali-metals. It is silver-white, malleable and 
very soft at ordinary ence: ieee Thrown on water it bursts 
into flame, and swims about on the surface like woedaet and 
rubidium, It inflames in ahs air when not protected. It fuses 
about 26°5°, passing through a pasty condition. Its specific 
gravity is 1°88 at 18° C.—La jebig’s Ann., cexi, 100, Jan., 1882. 
G F 
