Marcou’s Geological Map of the United States. 383 
_ The high temperature of moist air has frequently been ob- 
served. Who has not experienced the burning heat of the sun 
that precedes a summer’s shower? The isothermal lines will, I 
think, be found to be much affected by the different degrees of 
moisture in different places. ' 
Thirdly. The highest effect of the sun’s rays I have found to 
In Common Air. | In Carbonic Acid Gas. 
In shade. | In sun. | In shade. Tn sun. 
80 90 | 80 90 
81 94 84 100 
; 80 99 84 110 
‘ 81 100 85 120 
‘The receiver containing the gas became itself much heated— 
very sensibly more so than the other—and on being removed, it 
was many times as long in cooling. ; 
An atmosphere of that gas would give to our earth a high 
temperature; and if as some suppose, at one period of its his- 
tory the air had mixed with it a larger proportion than at pres- 
ent, an increased temperature from its own action as well as from 
Increased weight must have necessarily resulted. : 
On comparing the sun’s heat in different gases, I found it to 
be in hydr 
gas, 108 
ogen gas, 104°; in common alr, 106°; in oxygen 
; and in carbonic acid gas, 125°. 
Arn, XXXIL.— Review of a portion of the Geological Map of the 
United States and British Provinces by Jules Marcou ;* by WiL- 
_ Liam P. Buake. | 
_ and widely circulated among European geologists, are necessarily 
--‘Tegarded by us with no small degree of attention and curiosity. 
any approach to accuracy. : 
The oytieat a profile by M. J. Marcou, which 
has appeared in the Annales des Mines and in the Bulletin of 
i i 3 i du 
* Carte Géologique des Etats-Unis et des Provinces Anglaises de PAmérique 
_ ay Jules Marcou. Annales des Mines, 5° Séne, T. vii, p. 329. Published 
480 with the following : : : : 
Résumé explicatif , fan carte géologique des Etats-Unis dig. gears - 
uses de ! Amérique du Nord, avec un profil géologique allan M Sul * 
ppi aux cétes du Pacifique, et une planche de f es, 
Bulletin de la Société @éologique de France. Mai, 1855, p. 815. 
