the difference between
shoemakers and tailors. "The one is thrown upon his own resources, the
other works in the company of his fellows: the one thinks, the other
communicates. Cooke was a man of natural ability, and he made the best
use of his powers. Opportunity, sooner or later, comes to nearly all
who work and wait, and are duly persevering. Shoemaking was not found
very productive; and Cooke, being fairly educated as well as
self-educated, opened a village school. He succeeded tolerably well.
He taught himself geometry and mathematics, and daily application made
him more perfect in his studies. In course of time an extraordinary
ambition took possession of him: no less than the construction of a
reflecting telescope of six inches diameter. The idea would not let
him rest until he had accomplished his purpose. He cast and polished
the speculum with great labour; but just as he was about to finish it,
the casting broke! What was to be done? About one-fifth had broken
away, but still there remained a large piece, which he proceeded to
grind down to a proper diameter. His perseverance was rewarded by the
possession of a 3 1/2 inch speculum, which by his rare skill he worked
into a reflecting telescope of very good quality.

He was, however, so much annoyed by the treacherously brittle nature of
the speculum metal that he abandoned its use, and betook himself to
glass. He found that before he could make a good achromatic telescope
it was necessary that he should calculate his curves from data
depending upon the nature of the glass. He accordingly proceeded to
study the optical laws of refraction, in which his knowledge of
geometry and mathematics greatly helped him. And in course of time, by
his rare and exquisite manipulative skill, he succeeded in constructing
a four-inch refractor, or achromatic telescope, of admirable defining
power.

The excellence of his first works became noised abroad. Astronomical
observers took an interest in him; and friends began to gather round
him, amongst others the late Professor Phillips and the Rev. Vernon
Harcourt, Dean of York. Cooke received an order for a telescope like
his own; then he received other orders. At last he gave up teaching,
and took to telescope making. He advanced step by step; and like a
practical, thoughtful man, he invented special tools and machinery for
the purpose of grinding and polishing his glasses. He opened a shop in
York, and establish