SADIE ST ORS SS DIANA: 339 
in the past. Onthe contrary they were kept informed of the new- 
est discoveries and latest phases of geological thought and urged 
to judge for themselves of their importance and_ bearing upon 
previously attested principles. With all the varied lines of 
thought and discovery he kept in closest touch, and seemed 
equally appreciative of their value, whether they related to the 
eruptions of Kilauea, the Algonkian formation, Mesozoic mam- 
mals, the causes of oscillation of the earth’s surface, or what not. 
Of this progressiveness and appreciation of all additions to the 
sum of geological knowledge his newly published Manual gives 
sufficient evidence. 
The quality in an investigator which, other things being equal, 
he seemed to esteem most highly, was that of carefulness. How 
often were his students advised to trust or to doubt the state- 
ments of an author according as he was or was not, in the opinion | 
of Professor Dana a careful man. With hasty and ill-considered 
conclusions or elaborate theories built from meager observa- 
tions he had no patience, but to opinions which he believed 
had been derived from a careful and thorough study of facts, 
he was ever ready to give the fullest consideration, however much 
they might be opposed to his previous conclusions. ‘‘ More,” 
he said, ‘‘could be learned by studying unconformities than con- 
formities,”’ and this he believed to be as true of unconformable 
opinions as of heterogeneous strata. 
The awakening in his mind of the interest in science which 
became the ruling passion of his life, and led to his signal achieve- 
ments for its advance, Professor Dana used to ascribe largely to two 
causes, one that of having spent much of his early life in the 
country, the other, his first teacher. In connection with the first 
he used to deplore the lack of development of the faculties of 
observation and the ignorance of nature consequent upon life in 
the city and placed a high estimate upon the education uncon- 
sciously gained by an association with the beings and phenomena 
of the natural world. Asan illustration of this the author recalls 
an occasion when having passed in vain nearly around the class 
_ for a statement of the differences between a moss and a phenog- 
