482 Scientific Intelligence. 
SCIENTIFIC INTELLIGENCE. 
I. CHEMISTRY AND PHYSICS. 
1. New Determinations of Atomic Weights.—The results which 
have recently been reached with the rarer earths by successive 
fractional precipitations or decompositions, showing that ele- 
ments whose oxides are closely allied in properties may yet have 
widely different atomic weights, have led Marianac to submit 
some of the more common oxides to a similar course of fractional 
rogressive variation in 
the atomic weight. In the case of bismuth, a solution of the 
208-82, 208-08, 20856; the mean being 208°60. A second set of 
experiments was made by converting a known weight of the 
oxides obtained by fractioning into sulphates and weighing. Six 
determinations gave 208-06, 207-94, 208713, 208°33, 208711 and 
208°36 ; or 208°16 as the mean. To prepare the manganese oxide 
the nitrate was partially precipitated by oxalic acid, the filtrate 
evaporated to expel excess of nitric acid, diluted and again pre- 
cipitated with oxalic acid as before. Seven separate f ractions as 
oxalates were thus obtained, of which 1, 3, 5 and 7 were Cole 
verted into oxide by roasting, and this reduced to manganous 
d ¢ 
and the chlorine determined in a weighed portion by titrition. 
65°28; OF 
nesium two sets of experiments were made. In the first, magne 
sium nitrate was fractionally calcined, giving five successive 
yy * 
* 
