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posed to the local director of mines, Jean de Charpentier, in 1815, 
but that scientist only laughed at the absurd notion. Nearly ten 
vears later, he told his belief to Venetz, who gave it credence and 
embodied it in a paper read in 1823. This paper won the serious 
consideration of Charpentier in 1836. It was Charpentier who 
brought the hypothesis to the attention of Louis Agassiz, then 
living in Switzerland. 
In 1840, Agassiz demonstrated the former existence of glaciers 
in Great Britain and Ireland, and in the same year more fully de- 
veloped the glacial theory in his Etudes sur les Glaciers, which he 
dedicated to Venetz and Charpentier. 
The Geography of Ideas 
It should be noted that Perraudin lived in Switzerland, a land 
where boulders, similar to those in the Brooklyn Botanic Garden, 
and giaciers were an almost universal feature of the landscape. 
Agassiz, also, lived all of the early part of his life in Switzerland. 
Moreover, in Switzerland, one could (in Agassiz’s time as now) 
observe the very process by which the boulders were being trans- 
ported. The transporting agents there are the valley glaciers of 
the Alps. 
Fic. 9. Glacial Grooves, Inwood Park, Manhattan, New York City. 
View facing north. 
