282 M. L. Cordier on the Temperature of 



contraction, or for occasioning new solutions of continuity in 

 these masses. Let it be added, that the slow formation of new 

 solid strata in the interior, must be conformable to the general 

 rule, in virtue of which substances in the fluid state experience 

 a great diminution of volume in passing to the solid state. 



15. The least flexible regions of the earth'^s crust are neces- 

 sarily those near the surface, for the transverse solutions of con- 

 tinuity which they contain, have long since attained and lost their 

 maximum of separation. It is evident that the central forces 

 tend to bring nearer to each other the elementary masses of the 

 superficial regions, in proportion as the cooling contracts more 

 and more the volume of all the internal parts of the globe. 

 This approximation would act in a uniform manner, if the strata 

 of the consolidated crust were concentric, and if all the transverse 

 solutions of continuity were directed in planes perpendicular to 

 the surface ; but this is not the case. The shattered state of the 

 primordial crust is such, that, considering it in the great scale, lean 

 only define it as a heap of fragments pressed against each other, 

 and of which the strata are always very much inchned or vertical. 

 Since the establishment of this state, the obliquity of an innumera- 

 ble quantity of solutions of continuity, of which some have an im- 

 mense extent, forms an obstacle to the establishment in all points 

 of an approximation of the elementary masses that might be uni- 

 form and proportionate to the central contractions. Changes of level 

 of no great extent, but which may have affected great continen- 

 tal surfaces, have been substituted for this approximation. Many 

 geological facts agree with this hypothesis. It is to be presum- 

 ed that this efi^ect still subsists at the present day, although in 

 an imperceptible manner. If the secular raising of the basin of 

 the Baltic is constant, it may be accounted for in this manner. 

 The above hypothesis will also explain the change in the level 

 of the Mediterranean, which we observed with Dolomieu on the 

 shores of Egypt *. There is reason to think, according to our 

 opinion, that at present this part of the African continent is un- 

 dergoing a progressive lowering, which may amount to two or 

 three centimetres in a century. 



16. M. de Laplace, estimating the astronomical observations 



• See my description of the ruins of San (the Tanis of the ancients), in 

 the great work on Egypt. 



