The pernicious impost upon flint glass having at length been removed by the English Government, an opportunity was afforded to our native opticians to recover the supremacy which they had so long lost. It is to Thomas Cooke, more than to any other person, that we owe the recovery of this manufacture. Mr. Lockyer, writing in 1878, says: "The two largest and most perfectly mounted refractors on the German form at present in existence are those at Gateshead and Washington, U.S. The former belongs to Mr. Newall, a gentleman who, connected with those who were among the first to recognise the genius of our great English optician, Cooke, did not hesitate to risk thousands of pounds in one great experiment, the success of which will have a most important bearing upon the astronomy of the future."[7] The progress which Mr. Cooke made in his enterprise was slow but steady. Shortly after he began business as an optician, he became dissatisfied with the method of hand-polishing, and made arrangements to polish the object-glasses by machinery worked by steam power. By this means he secured perfect accuracy of figure. He was also able to turn out a large quantity of glasses, so as to furnish astronomers in all parts of the world with telescopes of admirable defining power, at a comparatively moderate price. In all his works he endeavoured to introduce simplicity. 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. William Gray, Solicitor, of York, one of his earliest friends, bought a 6 1/2-inch telescope in 1853. In the following year, Professor Pritchard of Oxford was supplied with a 6 1/2-inch. The other important instruments were as follows: in 1854, Dr. Fisher, Liverpool, 6 inches; in 1855, H. L. Patterson, Gateshead, 7 1/4 inches; in 1858, J. G. Barclay, Layton, Essex, 7 1/4 inches; in 1857, Isaac Fletcher, Cockermouth, 9 1/4 inches; in 1858, Sir W. Keith Murray, Ochtertyre, Crieff, 9 inches; in 1859, Captain Jacob, 9 inches; in 1860, James Nasmyth, Penshurst, 8 inches; in 1861, another telescope to J. G. Barclay, 10 inches; in 1864, the Rev. W. R. Dawes, Haddenham, Berks, 8 inches; and in 1867, Edward Crossley, Bermerside, Halifax, 9 3/8 inches.