120 Analysis, ^c. of Cordier''s Essay upon the 



" 8. If the crust of the earth has really been thus formed, the 

 primitive strata, known to us, ought to be disposed nearly in the 

 order of their fusibility. I say nearly, for it ought to have some 

 effect on the rapid action with which the process of cooling took 

 place at its commencement; and of the action also of chemical 

 affinities operating on such immense masses. 



" 9. Hence, the mean thickness of the crust of the earth does 

 not exceed twenty lea.^ues of five thousand metres, (about sixty- 

 two miles English.) I would even say, that according to some 

 geological data not yet followed out, and to which I shall on some 

 future occasion return, the mean thickness is much less. Abid- 

 ing by the result above mentioned, this mean thickness would 

 not quite equal one-sixty-third part of the mean radius of the 

 earth. It would be but the four-hundredth part of the ascertain- 

 ed length of a meridian." 



M. Pallas somewhere calculates the thickness of the prim- 

 itive formations at twenty-one miles. In travelling along the 

 main road from Richmond to Charlottesville, in Virginia, 

 the reviewer of this paper and Mr. Vanuxem noted, as well 

 as we could, the distances at which the strata changed, from 

 the granite at Richmond, to the disappearance of the primi- 

 tive ; and we thought the primitive strata, thus passed over, 

 could not be less in thickness than forty miles, making the 

 usual allowance in calculation. 



" 10. It is probable that the thickness of the crust of the earth 

 is very unequal. This seems to follow from the increase of sub- 

 terranean temperature from one country to another. Differ- 

 ence of conducting power, is not alone sufficient to account for 

 the fact. Several geological data tend also to the same conclu- 

 sion. 



"11. The heat proper to the soil of each locality, and thence 

 gradually disengaged, being the fundamental element of the cli- 

 mate of that locality (?) — and as in our opinion, (M. Cordier's) 

 the quantity of heat disengaged is not in any constant relation 

 between one country and another, we may conceive how, ceteris 

 paribus, countries in the same latitude may have different cli- 

 mates ; and how Mairan, Lambert, Mayer, and other philoso- 

 phers have failed, when they sought to represent by fbrmuliB 

 the gradation which the mesne superficial temperatures follow, 

 from the equator to the pole; and which they presumed to be 

 regular. We have contributed here a new cause, in addition to 

 those which occasion the singular inflexions exhibited by isother- 

 mal lines. 



