hundred years after his
death. But his name, though long forgotten except by astronomers, is now
engraved on marble in Westminster Abbey. Had his life been spared, it
would have been difficult to foretell to what eminence and fame he might
have risen, or what further discoveries his genius might have enabled
him to make. Few among English astronomers will hesitate to rank him
next with the illustrious Newton, and all will agree with Herschel, who
called him 'the pride and the boast of British Astronomy.'

WILLIAM GASCOIGNE was born in 1612, in the parish of Rothwell, in the
county of York, and afterwards resided at Middleton, near Leeds.

He was a man of an inventive turn of mind, and possessed good abilities,
which he devoted to improving the methods of telescopic observation.

At an early age he was occupied in observing celestial objects, making
researches in optics, and acquiring a proficient knowledge of astronomy.

Among his acquaintances were Crabtree and Horrox, with whom he carried
on a correspondence on matters appertaining to their favourite study.

The measurement of small angles was found at all times to be one of the
greatest difficulties which astronomers had to contend with. Tycho Brahe
was so misled by his measurements of the apparent diameters of the Sun
and Moon, that he concluded a total eclipse of the Sun was impossible.

Gascoigne overcame this difficulty by his invention of the micrometer.
This instrument, when applied to a telescope, was found to be of great
service in the correct measurement of minute angles and distances, and
was the means of greatly advancing the progress of practical astronomy
in the seventeenth century. A micrometer consists of a short tube,
across the opening of which are stretched two parallel wires; these
being intersected at right angles by a third. The wires are moved to or
from each other by delicately constructed screws, to which they are
attached. Each revolution, or part of a revolution, of a screw indicates
the distance by which the wires are moved.

This apparatus, when placed in the focus of a lens, gives very accurate
measurements of the diameters of celestial objects. It was successfully
used by Gascoigne in determining the apparent diameters of the Sun,
Moon, and several of the planets, and the mutual distances of the stars
which form the Pleiades.

Crabtree, after having paid Gascoigne a visit in 1639, describes in a
letter to Horrox the impression cr