156 THE MEANING OF EVOLUTION 
it was accomplished, it was still God’s plan and God 
carried it out. 
Now that we have tried to stretch our imagination 
back to the origin of our globe, the question not un- 
naturally comes to our mind, how long ago did all this 
happen? Is there any possible means of telling when 
the history of the earth began? All such attempts 
lead either to indefinite or to uncertain conclusions. 
Each man who essays the problem approaches it from 
a different side and ends with a different result. But 
no matter what the method of approach, all are agreed 
on at least one point, the enormous length of time, as 
counted in years, through which the earth has lasted. 
One great mathematician worked on the basis of 
the rate of the present cooling of the earth. Count- 
ing backward to the time when the earth’s surface 
must have been hotter, according to La Place’s idea, 
he decided that our globe has been cool enough for the 
existence of life upon it for a period of somewhere 
in the neighborhood of one hundred million years. 
Those who try to study the rate at which mud is 
being deposited in our bays and at the mouth of our 
rivers, and who hence try to deduce how long it has 
taken to produce the thickness of all the stratified rock 
we know, arrive at a figure larger, rather than smaller, 
than that mentioned above. The same is true of those 
who try to count the age of the earth by the rate at 
