Chemistry. 117 
€ a new oxyd of arsenic. In fusing nitric acid the compound 
of the nose. Its poisonous character may be readily inferred.—Pogg, 
Ann,, exviii, 615, .G. 
8. On the crystalline form of sulphate of thallium.—Victor von Lan@ 
has measured crystals of sulphate of thallium which are isomorphous 
with sulphate of potassium. The observed rhombic faces were 100, 010, 
110, 210, 101,111. The ratio of the axes is for 
ThSO,, a@:b:¢c=1: 0°7319 : 0°5539 
and for KSO,, a@:b:ce=1: 0°7464:0°5727 
The surfaces reflected very well and exhibited an adamantoid lustre, prob- 
ably in consequence of the large quantity of thallium in the salt. C) 
position of the optical axes of elasticity corresponded with that in sul- 
phate of ammonium but not with that in sulphate of potassium.—Pogg. 
Ann., exviii, 630. . @ 
4. On a crystallized hydrate of soda.—Harms has obtained a well 
crystallized and definite hydrate of soda by exposing a solution of caustic 
soda of density 1:385 to a temperature of 0° C. The crystals are often 
very large, have a glassy lustre and are perfectly transparent and color- 
less ; they fuse at 6° C. and yield a solution of density of 1:405. As the 
author states that the crystals may be obtained very pure even from so- 
lutions which contain sulphate and chlorid of sodium, it seems probable 
that they will afford a ready means of obtaining pure soda solutions for 
laboratory use. The formula of the crystallized hydrate is NaO+-8HO ; 
oblique rhombic.—Pogg. Ann., cxix, 170. _ W.@ 
5. On the constitution of Columbite—H. Rose has published an ex- 
tended discussion of the minerals which contain hyponiobie acid. As 
Specially interesting to chemists we note simply the fact that in pure and 
undecom varieties the ratio of the oxygen in the acid to that in the 
bases is as 3 to 1, so that pure columbites may be regarded as mixtures 
of Nb,O, FeO with Nb,O, MnO. Rose calls attention to the iso- 
morvhism of columbite and wolfram, and remarks further that the ob- 
servations of Nordenskiéld, ‘and later of himself, go to prove that hypo- 
i in the uncombined sta‘ 
niobie and tungstic acids are isomorphous in te, 80 
