d+ Th eA MePrican Geologist. February, 1892 
satisfactory proof of the being of God must be rooted in « priori 
evidence. Illustrations from nature are all useful on the ante- 
cedent proof that there is any reality whose being and attributes 
are illustrated. With such maturing views he wrote one or two 
hundred pages again and yet again, during the succeeding years ; 
but a few months lapse of time so changed his conception of the 
most appropriate treatment that all which had been written was 
rejected. Out of some portions several articles were prepared 
for the Methodist Quarterly Review (April, 1875, and Jan., 1874), 
viz: The unity of the physical world, and Religious ideas among 
barbarous tribes (Jan., 1875). Some of his maturer views were 
also embodied in a review of Cocker’s Christianity and Greek 
Philosophy (July, 1872). 
1868. During 1868 circumstances directed his attention par- 
ticularly to the popularization of science. He had written, in 
1858, a series of popular geological articles for the Michigan 
Journal of Education, and later had written a similar series for 
the Ladies’ Repository, of Cincinnati, under the general title 
Voices from Nature, and at the special request of the editor, Rey. 
Dr. D. W. Clark. These Dr. Clark had suggested to him to have 
published in book form, under the title of Zhe Geologic Ages, 
but he was not satisfied with the treatment he had there given the 
subject, and resisted Dr. Clark’s flattering solicitation. 
He was beset, however, on every side, by requests for popular 
articles, most of which he hf&id to refuse. However, from his pen 
appeared three articles in-the ‘‘ University Magazine,” four in the 
‘College Courant,” and three in the ‘‘Western Monthly.” He 
conceived also an extension of the project of popular lectures, in 
which the grand conclusions of the sciences should be set forth in 
more glowing and popular style than till then had been customary 
with scientific lecturers of good scientific standing. His ex- 
perience in composition had convinced him that the public pos- 
sessed an appetite for solid information, though they demanded it 
well spiced. Contrary, therefore, to the precedents of his elders 
and the strong conservative judgment of the leaders in science, he 
boldly took the risk of an attempt to present science in a popular 
garb. The result was about what he had anticipated. While 
fair audiences of deeply interested people attended his lectures, 
there were crowds who would be attracted only by a great and pop- 
ular name or a public entertainment which, either in its subject 
