250 Marcel de Serres on the Old World 
The Old World compared with the New World. By M. 
MARCEL DE SERRES, Professor of Mineralogy and Geo- 
logy at Montpellier.* 
The Earth, like Man himself, has had its different phases ; 
after having passed through its infancy, it has now reached 
mature age, and it is in this state that it presents itself to 
our notice. Our globe is far indeed from having always 
been what it is in the present day, and we shall endeavour 
to trace the various modifications it has undergone at dif- 
ferent periods of its history (See Note 1, p. 258). 
The air we breathe, for example, is not the same as that 
from which the beings that preceded us here below derived 
the powers of life (See Note 2). The seas which cover 
nearly three-fourths of the earth’s surface (See Note 3), have 
been more extensive still at the time when continents scarcely 
equalled the extent of moderate sized islands (See Note 4). 
None of the animals which now people our planet, nor the 
vegetables by which it is adorned, existed in those remote 
ages, when there was no human being to behold them. 
I have said that the atmosphere was not the same in com- 
position in former times as itis now. Let us examine what 
proofs we have for this fact, which is the more singular 
from no change having appeared in it during historical times, 
and indeed scarcely seems possible. 
Primitive vegetation, of the kind most remarkable for 
vigour and beauty, has left us indubitable proofs of it. 
These are to be found in the immense masses of coal, the 
remains of the ancient forests which covered the surface of 
the earth. But from what quarter have the trees of these 
forests derived this vast quantity of carbon, now become 
the source of so many industrial occupations? Did it exist 
in the soil? The soil could not supply it, since as yet it con- 
tained neither humus nor any kind of vegetable substance. 
They found it in the great proportions of it which existed in 
the atmosphere (See Note 5). This excess of carbonic acid was 
* Outline of a Lecture lately delivered by M. Marcel de Serres. 
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