e 
Chemistry and Physics. 417 
half the width of the opening with a height of five millimeters; the 
inner border of the plate was parallel to the slit of the collimator. The 
I 
the following wave-lengths, taking Fraunhofer’s value for D, namely, 
5888 ; 
A 7602 C 6557 E 5266 G 4305 ae 
3969 border 
B 6865 Da F 4858 Hf 3967 centre. 
only original part of his paper—that the arrangement he proposes 
will give a simple and precise method of classifying the spectral lines, 
d 
—Comptes Rendus, lviii, 1153. WG 
3. On the atomic weight of Thorium and the formula of Thoria.—De- 
being in each case resolved by sulphuric acid in the manner recom- 
mended by Marignac for cerite. The sulphate of thoria is heavy, white, 
the mass changes to clear and colorless crystals, which, according to 
arignac, belong to the oblique rhombic system. The sulphate was 
dried at 
. Upon this view, the sulphates must be written 2(ThO,, 
“Am. Jour. Scr.—Snconp Serres, VoL. XXXVIII, No. 114—Nov., 1864 
33 
> 
