Miscellanies. | 405 
b. 100 models; the same as above, with 77 secondary forms, 
$6,66, (164 florins.) 
All the specimens of the different collections are well selected and 
fresh, so as to be perfectly adapted for studying as well as teaching. 
Each specimen is accompanied by a ticket, indicating the name of 
the substance and the place where it is found. In case it is desired, 
the labels will be given both in French and English. ‘The collec- 
tions, also, if it is wished, will be arranged according to any other con- 
venient system. We can furnish, also, collections of every species 
in greater numbers, larger size, and more rich in rare and precious 
minerals and crystals, at any other prices that may be agreed on. 
Accurate catalogues of our Magazine of Minerals of rocks and petri- 
factions are distributed gratis. For accommodating the public, we 
have made an arrangement, by which all the objects above mention- 
ed may be obtained through any of the booksellers in Germany, who, 
on their part, must draw their orders upon the bookstore of M. J. B. 
Mohr, in this city. 
Le Comptoir de Minéraux a Heidelberg. 
Heidelberg, Feb. 28, 1828. 
J will only add, that I have a few copies of the catalogues of min- 
erals and petrifactions, (particularly of the latter) in this “ Comptoir,” 
and should be happy to loan them to any gentleman desirous of ex- 
aming them. Respectfully, &c. E. Hrrencock. 
‘Prof. of Chem. Min. &c. | 
Amherst, Oct. 19th, 1829. : 
8. Baron Humboldt’s Expedition.—At a meeting of the Acade~ 
my of Sciences, on the 12th of October, M. Gay Lussac communi- 
cated a letter, addressed to M. Arago by Baron Humboldt, dated 
August 18, 1829. “This celebrated naturalist,” says the Courier 
des Electeurs, from which we translate the account, “ having arrived 
at the remotest frontiers of Siberia, has accomplished the objects of 
end of November. ‘The Emperor of Russia has seconded this great 
enterprize with a munificence truly royal. Not content with causing 
he added to 
a mining engineer of distinguished merit. ‘1 cannot look upon 
these things,’ says the illustrious traveller, ‘as tokens. of personal 
kindness and consideration. They are a public homage paid to the 
