398 Correspondence of J. Nickles. 
Note to paper on the Earth’s Climate in Paleozoic Times.—Since 
the above was in type, my attention has been called by Prof. 
Dana to a paper published in 1849 by the late’ Major E. B. 
Hunt, U.S. Engineers, on Terrestrial Thermotics. In this paper, 
which appears in the Proceedings of the American Association for 
. > of 
that year, page 158, and is referred to by Dana in his Manual 
the earth’s surface increases with the barometric column; an 
that, as the atmospheric mass must have been greater in the 
earlier geological periods, by the amount of carbon and carbonie 
acid since abstracted from it, the temperature must have been 
igher. To this effect of the carbonic acid, is to be added, as 
Mr. Dana has remarked, the greater moisture of the insular 
climate of the Carboniferous period, when the excess of aqueous 
vapor would have contributed to increase the weight of the at- 
mospheric mass. 
The slight augmentation of the barometric column dependant 
upon these additions to the atmosphere would however probably 
be inadequate to produce the considerable difference in climate 
and Bravais, the Lotanist Moquin-tandon, the geologist Marcel de Serres, 
ching each of these savants, some of whom, as Bravais and Péan de — 
St. Gilles, have died in the prime of life and maturity of talent, without 
having been able to produce all that we could have expected from th 
attainments and zeal, 
César Mansuéte Despretz died at six in the morni 
: espr ng, March 15th, . 
1863. Born in Lessines, (Hainault), on the 13th of March, 1789, of 
poor parents, he was, to use an expression peculiar to France—the som 
of his works, Active, studious, very intelligent, and eager for instruction, 
he came to Paris, attended there the course of physics and chemistry, 
_ and speedily brought himself to the notice of Gay-Lussac, who : 
a8 deci 1 note of the patience and perseverance of his young scholar, and 
chose him as assistant professor in hi “oly 
his course of chemistry at the. 
oj a eh I aa a Fi i ee 
ceed 
