LECTURES. 6 1 



were the motion of the glacier thirty inches a year the 

 period would be forty times that amount or 1,000,000 

 years; if, on the other hand, the motion were faster, the 

 time would decrease in proportion. The rate of 

 time necessary to accomplish a given object may not 

 always correspond with the numerical calculations of 

 writers. Experiments in the chemical laboratory 

 are sufficiently numerous to show the different actions 

 of the same substance under different conditions, 

 say some substances precipitate in 10 minutes with 

 sufficient heat that might otherwise remain 

 10 or 10,000 years without that heat, and 

 to make us pretty careful as to how we lay down a 

 law upon insufficient evidence. Hence, our given 

 geological time must be more or less hypothetical 

 under any circumstances. ED] 



"Large animals being found imbedded in the ice 

 are evidence of its coming quickly. It is not likely 

 that a snow storm capable of freezing large animals 

 in Siberia and North America would be limited to 

 one particular region. It would be graded according 

 to latitude. The question is, how much was there in 

 the coldest latitude; how much in the warmest? Let 

 no one fail to urge upon the members of any expe- 

 dition to the Arctic regions the importance of ascer- 

 taining the motion of Arctic icebergs and glaciers. 

 This motion can be ascertained by the amount of ice- 

 bergs which float away from their extreme southern 

 limit." 



It is thus that we learn the first principles of gla- 

 cial action. How careful our instructor is to distin- 

 guish facts as truths; and possibilities, only, he weaves 

 into theories, which he is very careful to impress 

 upon us arc possibilities. In a letter made public 

 some years since, he said: "The office of Science is 

 not to record possibilities, but to ascertain what Na- 

 ture does," again as far as one "deals with mere ar- 

 guments of possibilities or even probabilities, with- 

 out a basis of fact," he says, that one "departs from 

 the true scientific method." These words are as true 



