474 Catalogue Raisonné. 
Sur le pouvoir Magnétisant, §c. On the Magnetizing Power 
of the Solar Rays ; by MM. P. Rizss and L. Moser,—<Ann. de 
Chim. Nov. 1829. 
“ The surest method of judging of the magnetism of a needle,” say the 
authors of this memoir, “ is by making it oscillate;” and this plan they 
have followed in their experiments. 
The observations on the magnetizing influence of the solar rays, conducted 
by Morichini, Mrs. Somerville, Baumgartner, Christie, and more lately, 
the essay of M. Zantedeschi, (vide Vol. I. p. 152. of this Journal,) have, 
in comparison with other experiments, involved this question in extreme 
doubt. In the present unsettled state of opinion, all new facts are desir- 
able, and MM. Riess and Moser have supplied their mite of information. 
The needles they used were of wrought steel; their size was very small, 
but they presented a considerable surface to the influence of the light. 
By examining them some time before use, the experimenters made them- 
selves minutely acquainted with their magnetic intensity. 
The result of the labours of MM. Riess and Moser, is the total rejection 
of a discovery which for a period of twenty-seven years has been a mat- 
ter of discussion. 
Note sur une nouvelle combinaison, &c. Notice of a new natu- 
ral combination of the Carbonates of Lime and Soda, differing from 
Gay-Lussite. By M. Germain Barrvue..—Lobid. 
This mineral, whose structure is laminar, presents without difficulty three 
directions of cleavage, giving a rhomboedron similar to that of primitive 
carbonate of lime, as far as the author could judge without a goniome- 
is There are appearances of a cleavage in the direction of the small 
iagonal. 
The transparence is perfect in fragments which are clear; the lustre is 
glassy, similar to that of arragonite. It marks carbonate of lime deep- 
ly, arragonite with difficulty: the needles of arragonite also mark this 
substance, but very slightly. The powder is white. Sp. gr. 2.921. 
The double refraction is the same as that of Iceland spar. 
It dissolves entirely with effervescence in nitric acid. With the blowpipe, 
heated alone, it decrepitates a little at first, then becomes brown, and is 
nt reduced to lime, but with more difficulty than pure carbonate 
of lime. 
its powder melted with borax dissolves with effervescence. A milky glo- 
bule is obtained, demi-diaphanous, slightly pearly, becoming opaque and 
dull after long contact with the air. 
The result of analysis is, 
Gangue, - = 0,050 
Per-oxide of iron, 0.010 
Carbonate of lime, 0.700 
Carbonate sf soda, 0.140 
Water, - = 0.097 

0.997 
4, €. Carbonate of lime, 11 atoms. 
é Carbonate of soda, 2 atoms. 
Water, - about 9 atoms. 
Lettre de M. Pelletier, §c. Letter from M. Pelletier to M. Gay- 
Lussac on a New Alcaloid.—Jbid. 
The true Peruvian bark is generally adulterated with a bark exactly re- 
sembling it in appearance, and possessing a similar taste, but without 
its medicinal qualities. It may, however, be well distinguished by the 
application of a little concentrated nitric acid, which converts the colour 
of the true cinchona into a red brown, whilst it gives to the adulterating 
substance a deep green colour. 
