, and dropping
his work only to take it up when he had had the necessary sleep.
A strong constitution might stand this for a few years, as his did.
But the ultimate result hardly needs to be told.

Besides the volume I have mentioned, Wright's letters were collected
and printed after his death by the subscription of his friends.
In these his philosophic views are from time to time brought out
in a light, easy way, much more charming than the style of his
elaborate discussions. It was in one of his letters that I first
found the apothegm, "Men are born either Platonists or Aristotelians,"
a happy drawing of the line which separates the hard-headed scientific
thinker of to-day from the thinkers of all other classes.

William Ferrell, a much older man than myself, entered the office
about the same time as I did. He published papers on the motions
of fluids on the earth's surface in the "Mathematical Monthly,"
and became one of the great authorities on dynamic meteorology,
including the mathematical theory of winds and tides. He was, I
believe, the first to publish a correct theory of the retardation
produced in the rotation of the earth by the action of the tides,
and the consequent slow lengthening of the day.

James Edward Oliver might have been one of the great mathematicians of
his time had he not been absolutely wanting in the power of continuous
work. It was scarcely possible to get even his year's office
work out of him. Yet when I once wrote him a question on certain
mathematical forms which arise in the theory of "least squares,"
he replied in a letter which, with some developments and change of
form, would have made a worthy memoir in any mathematical journal.
As a matter of fact, the same thoughts did appear some years after,
in an elaborate paper by Professor J. W. L. Glaisher, of England,
published by the Royal Astronomical Society.

Oliver, who afterward became professor of higher mathematics at
Cornell University, was noted for what I think should be considered
the valuable quality of absent-mindedness. It was said of him that
he was once walking on the seashore with a small but valuable gold
watch loose in his pocket. While deep in thought he started a kind
of distraction by picking up flat stones and skipping them on the
water. Taking his watch from his pocket he skipped it as a stone.
When I became well acquainted with him I took the liberty of asking
him as to the correctness of this story.