318 BOTANICAL INFORMATION. 
botaniques en Algérie, et de visiter, en particulier, la portion du désert 
ou Sahara Algérien qui avoisine Biskara. 
Nous espérons, Monsieur, que vous voudrez bien nous honorer de 
votre adhésion, et nous vous prions de vouloir bien faire parvenir votre 
réponse dans le plus bref délai possible à M. Balansa, Rue Suger, 1, 
à Paris, ou à M. Ernest Cosson. 
Paris, le 22 Juillet, 1851. 
P.S.—Nous profitons de cette occasion pour vous informer qu’il reste 
à la disposition des souscripteurs un certain nombre des collections de 
M. Jamin (environ 100 espèces), recueillies en 1850 aux environs 
d'Alger, ainsi qu'une centurie de plantes intéressantes recueillies en 
1850, par M. Dœnen, dans le Val Lassina, Lombardie. 
Mrcroscorss of the late PROFESSOR LINK. 
Two excellent microscopes, used by Professor Link for preparing his 
representations of the microscopical anatomy of plants, are to be sold 
at Berlin. One of these instruments was constructed by the celebrated 
optician, Plóssl, of Vienna. It has five ocular and six object-glasses, 
and magnifies by the first ocular from 25 to 210 times, and by the last 
1145 times. A revolving micrometer, of excellent workmanship, and 
measuring with the greatest precision, a large prism and a large lens 
mounted on separate statives, both for illuminating, and various other im- 
plements, are added. The instrument cost altogether about £45. The 
lenses are in no way injured, nor the serews worn out. The other 
instrument is a catadioptrie microscope, by Professor Amici, of Florence, 
the discoverer of the pollen-tubes going down to the ovules. It is 
excellent for its achromatism and its large field of view. There is a 
fine prism for refracting objects. It has four ocular and five object- 
lenses. Its magnifying power reaches from 21 to 1558 times, or with 
the first ocular to 286 times. The object-lenses, separately mounted, 
are also used either alone or all together as a simplex. The object- 
table slides up and down, and is furnished with a turning diaphragm 
and two revolving micrometers, the one moving from side to side, the 
other forward and backward. Two. different kinds of camera lucida, 
. and various other implements, especially for illuminating and excluding - 
the false light, are added. This instrument has been but little used. 
~ Its price is said to have been about £45. Offers will be received by 
= Dr, Pritzel, Berlin, Alexandrinen-strasse, 88. 
