He left his mark on nearly every astronomical instrument.

He found the equatorial comparatively clumsy; he left it nearly perfect.

His beautiful "dividing machine," for marking divisions on the circles, four feet in diameter and altogether self-acting--which divides to five minutes and reads off to five seconds is not the least of his triumphs.
The following are some of his more important achromatic telescopes.

In 1850, when he had been fourteen years in business, he furnished his earliest patron, Professor Phillips, with an equatorial telescope of 6 1/4 inches aperture.

His second (of 6 1/8) was supplied two years later, to James Wigglesworth of Wakefield.