Physics and Chemistry. | 129 
before mixture. After reaction the magnetism is sensibly equal to 
the sum M,+M,. In the greater number of cases the formation 
of a precipitate exerts no disturbing influence. 
5.) Lhe atomic magnetism of hydrated oxyds is a little higher 
or lower than that of the corresponding salts. 
: The magnetism of precipitated hydrate of sesquioxyd of iron 
mereases rapidly, beginning at the moment of precipitation. The ° 
author attributes this tact to the colloidal state of the hydrate at 
the first moment of precipitation. The differences presented by 
the atomic magnetism of acetate of sesquioxyd of iron doubtless 
the same cause. ese differences are not remarked in 
the solution of hydrate of sesquioxyd of chromium, in caustic pot- 
ash, and in that of oxyd of nickel in ammonia. 
i.) The magnetism of the anhydrous oxyds of the magnetic met- 
als is notably less than that of the saline combinations of these 
(8.) With the exception of sulphate of manganese, the magnetism 
of the sulphates of the magnetic metals is very feeble. 
(9.) The magnetism of the cyanids of nickel and cobalt disappears 
d dissolved in cyanid of 
the action of concentrated solar or electric light. The author’s 
9 18 too fall of detail to admit of an abstract, but we shall give 
2 lew of the more salient results. A tube 2°8 feet long and 2°5 
‘ches internal diameter is closed at both ends by glass plates. 
may be connected with an air pump and with a series of tubes used 
shower of liquid spherules was precipitated on the on. On 
“peating this experiment with a con beam of light forming 
eight inches long, the cone which was at first invisible 
suddenly like a luminous spear. The rapidity of the con- 
action ‘diminished with the density of the light. The 
Same effects were produced when oxygen or hydrogen were 
Aw. Jour. Scr.—Szconp Sentes, VoL. XLVI, No. 139.—Jan., 186% 
9 
