8 PROCEEDINGS OF WASHINGTON MEETING. 



Lecture room, first into the law lecture room, and then into the general 

 assembly hall of the university, where it was estimated that from 

 twelve hundred to fifteen hundred listeners waited and were instructed 

 for an hour and a quarter on the occasion of his third lecture. This 

 was the last time he was outside of his home, and he was so weak that 

 some friendly students literally bore him to the carriage which was wait- 

 ing to convey him back. 



He certainly expected to recover so as to be able to deliver the final 

 lecture of the course, though evidently there were misgivings — misgivings 

 whose shadowed presence in his calculations for some months previous 

 can be read from small acts and sayings which are now recalled, but 

 which at the time attracted but little attention. 



After he had definitely chosen as the arena in which he should work 

 out his professional career and had been appointed to teach the natural 

 sciences, there are distinctly two epochs in his life which are separated 

 from each other by an important official event. The first epoch is that 

 which is marked by his devotion to rigorous scientific investigation, the 

 discovery of the unknown. The second epoch isthatmarked by his broader 

 grasp of things already known in science, and his classification of the known 

 into system. It will not be correct to suppose that he wholly abandoned 

 one when he took up the other, or that he did not already labor in the 

 latter before he gave up the former ; for throughout his life he was ready 

 to engage, and did engage, in either as opportunity was presented. Still, 

 he did himself make announcement of this transition from the special to 

 the general in his scientific labor. This distinction and division were 

 instituted by his giving up of the geological survey of Michigan and 

 abandonment of all hope of future work in that direction, and were 

 accentuated later by his acceptance of the chancellorship of the Syracuse 

 university. The war of the Rebellion interrupted the Michigan survey 

 in 1861, after two years of successful field and laboratory work. The 

 official result of these two years is embraced in a volume of 339 pages, 

 printed in 1861* But the most valuable results appeared unofficially 

 in later publications, chiefly in the proceedings of the Academy of 

 Natural Science of Philadelphia, the American Journal of Science, and 

 the proceedings of the American Philosophical Society. During the eight 

 years that elapsed before the survey was revived (1869) he was mainly 

 engaged, so far as strictly geological work was concerned, in elaborating 

 its paleontological results and in special surveys of limited districts with 

 special reference to their economic resources. Thus he became familiar 

 with the geological conditions of the salt and petroleum rocks of Michi- 



* First Biennial Report of Progress of the Geological Survey of Michigan: Lansing, 1861, 



