178 
Agassiz came to America in 1846, and in 1847 he became a pro- 
fessor in Harvard College. During his first year in America, he 
made his observations of glacial phenomena near Halifax, includ- 
ing erratic boulders and glacial striations. 
A Bold Inference 
If the boulders of Switzerland are transported by glacial ice, as 
anyone may actually observe, might it not be possible, or even 
probable, said Agassiz, that the erratic boulders of North America 
were also transported by the same agency ? 
How profoundly one’s ideas are affected by his environment! 
\ native of Holland, for example, who had always lived in that 
country, a resident of the prairies of the United States, or of 
Australia, coulc 
ery 
| 
hardly have made even a good guess as to what 
agency had transported the boulders of Long Island or other parts 
of North America. If Timothy Dwight, after his keen observa- 
tion of the Long Island boulders, described above, had lived sev- 
eral years in Switzerland, it is conceivable that he might have 
drawn the comparisons made by Agassiz and so have become the 
father of the glacial theory. 
But by what ice could the North American boulders have been 
transported? “ Glacial ice hardly seemed probable, for never, 
within recorded history has the boulder strewn region of America 
been occupied by glaciers.” Yet to Agassiz no other explanation 
seemed adequate. 
The Proof of the Pudding is in the Eating 
Weil, in Science, when one infers an explanation of an observed 
phenomenon, the next thing he does is to test his inference or hy- 
pothesis. “If the hypothesis, based upon what I have already ob- 
served is true,’ so the reasoning goes, “ then certain results should 
logically follow; certain other facts may be predicted and the pre- 
diction will be found to be true.’ The hypothesis is used as a 
divining rod to discover additional facts; it is used as a yard stick 
to measure phenomena already observed; new facts are turned 
a 
upon the hypothesis like a search light for the purpose of discover- 
ing its flaws, or the contrary. [very relevant fact is passed in 
review in the light of the hypothesis, for the true scientist never 
