Geological Survey of Pennsylvania. 173 
XVIII. New works on Mineralogy and @eology.—Dr. 
Emmons, of the Rensselaer School, has published “ A Manual 
of Mineralogy and Geology ; designed for the use of schools, 
and for persons attending lectures on these subjects, as also a 
convenient pocket companion for travellers in the United States 
of America.”’ It is a duodecimo volume of 230 
_ Dr. Comstock of Hartford, has still more recently publish- 
ed “‘ Elements of Mineralogy, adapted to the use of semina- 
ries and private students.”’ ‘This is an octayo of 33S pages. 
XIX. Philosophical Institute of Nantucket—We are 
gratified to observe, that in this insular community—devote d 
necessarily, in a great degree, to commerce, there is a society 
for the cultivation of liberal knowledge. At a late meeting, 
an interesting memoir was read by the president, WALTER 
Fo.eer, Esq. on aerolites. It gives a succinct account of 
some of the principal events of this nature, and of some of 
the leading theories which have been published to account for 
them. The subject is highly inieresting, although veiled in 
mystery. All that we can do at present, is to register the 
facts. with great precision, and to analyse every new stone 
that falls. ‘Thus our successors will be furnished with ma- 
terials from which they may, in due time, be enabled to form 
a theory capable of proof. 
XX. Carpenter’s Memoir on the division or extinction of 
mercury by trituration.—We have not room for the insertion 
of this important paper, the principal object of which is to 
prove, that in the blue pill, the mercury is net in the state 
of oxid, but merely of minute division. The facts adduced 
by Mr. Carpenter, appear to establish his proposition, and 
contradict the common opinion, both with respect to the na- 
ture of the blue pill, and to the supposed inactivity of metal- 
lic mercury. r. Carpenter also recommends a new formu- 
la for the preparation of the blue pill. 
he memoir is worthy of the attentive perusal of the chem- 
ist and physician. 
XXI. Geological survey of Pennsylvania.—Proposals 
have been issued for making a geological and mineralogi 
survey of Pennsylvania, for publishing a series of geologi al 
maps, and forming state and county geological and minera~ 
Jogical collections. The maps will be projected, drawn, and 
