TS LAMARCK, HIS LIFE AND WORK 
in the mass of the terrestrial radii, has necessarily 
caused the earth’s centre of gravity to vary, as also 
its two poles.* Moreover, since it appears that this 
variation, very irregular as it is, not being subjected 
to any limits, it is very probable that each point of 
the surface of the planet we inhabit is really in 
the case of successively finding itself subjected to 
different climates.” He then exclaims in eloquent, 
profound, and impassioned language: 
“How curious it is to see that such suppositions 
receive their confirmation from the consideration of 
the state of the earth’s surface and of its external 
crust, from that of the nature of certain fossils found 
in abundance in the northern regions of the earth, 
and whose analogues now live in warm climates; 
finally, in that of the ancient astronomical observa- 
tions of the Egyptians. 
“Oh, how great is the antiquity of the terrestrial 
globe, and how small are the ideas of those who at- 
tribute to the existence of this globe a duration of 
six thousand and some hundred years since its origin 
down to our time! 
“The physico-naturalist and the geologist in this 
respect see things very differently; for if they have 
given the matter the slightest consideration—the one, 
the nature of fossils spread i in such great numbers in 
all the exposed parts of the globe, ‘both in elevated 
situations and at considerable depths i in the earth; the 
other, the number and disposition of the beds, as also 
the nature and order of the materials which compose 
the external crust of this globe studied throughout 
* Hooke had previously, in order to explain the presence of tropi- 
cal fossil shells in England, indulged in a variety of speculations 
concerning changes in the position of the axis of the earth’s rotation, 
a shifting of the earth’s centre of gravity analogous to the revolu- 
tions of the magnetic pole, etc.” (Lyell’s Przzciples). See also p. 132. 
