his country, and finally those creations of the Quaternion Calculus
by which new capabilities have been bestowed on the human intellect.




LE VERRIER.



The name of Le Verrier is one that goes down to fame on account of
very different discoveries from those which have given renown to
several of the other astronomers whom we have mentioned. We are
sometimes apt to identify the idea of an astronomer with that of a
man who looks through a telescope at the stars; but the word
astronomer has really much wider significance. No man who ever lived
has been more entitled to be designated an astronomer than Le
Verrier, and yet it is certain that he never made a telescopic
discovery of any kind. Indeed, so far as his scientific achievements
have been concerned, he might never have looked through a telescope
at all.

For the full interpretation of the movements of the heavenly bodies,
mathematical knowledge of the most advanced character is demanded.
The mathematician at the outset calls upon the astronomer who uses
the instruments in the observatory, to ascertain for him at various
times the exact positions occupied by the sun, the moon, and the
planets. These observations, obtained with the greatest care, and
purified as far as possible from the errors by which they may be
affected form, as it were, the raw material on which the