y a certain sensitiveness of
imagination, and quickness of sensibility, every thing he contemplates
becomes alive in his mind, and an object in which he takes a personal
interest. This gives wonderful distinctness to his exposition of
natural laws, and his delineation of the characters and pursuits of
men of science. His Copernicus, Kepler, Gallileo and Newton are not
dry enumerations of qualities, but vivid portraits of persons. He
seems in close intellectual fellowship with them as individuals, and
converses of them in the style of a friend, whose accurate knowledge
is equalled by his intense affection. So it is with his detail of the
discovery of a new law, or fact in science. His mind "lives along the
line" of observation and reasoning which ended in its detection, and
he reproduces the hopes, fears, doubts, and high enthusiasm of every
person connected with the discovery. His delineation of Kepler is
especially genial and striking. By following this method he infuses
his own enthusiasm into the reader, bears him willingly along through
the most abstruse processes of science, and at the end leaves him
without fatigue, and ready for a new start.

In the treatment of scientific discoveries, by minds like Mr.
Mitchell's, we ever notice an unconscious personification of Nature,
as a cunning holder of secrets which only the master-mind can wrest
from her after a patient siege. The style of our author glows in the
recital of the exploits of his band of astronomers, as that of a
Frenchman does in the narration of Napoleon's campaigns. This is the
great charm of his book, and will make it extensively popular, for by
it he can attract any reader capable of being interested in a tale of
personal adventure, ending in a great achievement. We can hardly bring
to mind a popular lecturer or writer on science, who has this power to
the extent which Mr. Mitchell possesses it. He himself has it by
virtue of the mingled simplicity and intensity of his nature.

One of the most striking lectures in Mr. Mitchell's volume is that on
the discoveries of the primitive ages, in which he represents the
processes of the primitive observer, with his unarmed eye, in
unfolding some of the laws of the heavens; and he indicates with great
beauty what would be his point of departure, and what would be the
limit of his discoveries. This lecture is a fine prose poem. There is
a passage in the introductory lecture which grandly represents the
continua