50 DOLLOND. 



the year 1750, occupying a small house in Vine Street, Spitalfields. 

 In 1752 John Dollond, who up till then had pursued his original 

 occupation, grew weary of pursuits so little in accordance with the 

 natural bent of his mind, and entered into partnership with his son, 

 in a house near to Exeter Change, in the Strand. Here father and 

 son began and continued that series of experimental researches 

 which, in June 1758, led to the memorable conclusion on which was 

 founded the construction of the Achromatic Refracting Telescope. 

 In the following year a patent was obtained for the exclusive sale 

 of these telescopes, but so limited were the means of the authors of 

 this invention, that, in order to defray the expenses of the patent, 

 they were compelled to sell a moiety of its value to an optician, 

 with whom they entered into partnership. Notwithstanding the 

 great practical value of this discovery, it produced little benefit for 

 some years to the owners of the patent. In 1761 John Dollond 

 died, leaving to his son Peter the task of carrying on the business 

 in partnership with the optician who had paid for the patent. This 

 connection was, however, of short duration, for the conduct of his 

 partner was so unsatisfactory, that in 1763 Mr. Dollond purchased 

 from him his share in the business for 200J., the full commercial 

 value of this most important discovery being considered at that 

 time to be worth only 400Z. Peter Dollond was now in possession 

 of the entire patent, and he was soon called upon to contest its 

 validity with the very man who had so lately been concerned in 

 protecting it. These suits were uniformly decided in favour of 

 Dollond, and although vexatious in their character, were of advan- 

 tage to him, not only in their immediate issue, but also in extending 

 the name, reputation, and sale of the object whose right of owner- 

 ship was contested. 



Mr. Dollond now began to be more generally known, and made 

 the acquaintance of many of the philosophical men of the time, 

 becoming intimate with Dr. Maskelyne, the Astronomer Royal at 

 that period, and with Mr. James Short, a man highly distinguished 

 in arts and science. To this latter gentleman he, in 1765, proposed 

 an improvement in the Achromatic Telescope, which Mr. Short laid 

 before the Royal Society, at the same time signifying that it had 

 his entire concurrence and approval. Among other works of Dol- 

 lond are an improvement of Headley's Quadrant, communicated to 

 the Royal Society, in 1772, by the Astronomer Royal ; and an 

 apparatus for the improvement of the Equatorial instrument, laid 

 before the Society, through the same medium, in 1779. 



Mr. Dollond had now earned for himself a well-deserved reputa- 

 tion. In 1786 the American Philosophical Society, unsolicited, and 

 with the approval of Benjamin Franklin, elected him a member of 

 their society. 



About the year 1766 the optical business had been removed from 

 the Strand to St. Paul's Churchyard, where it became so extensive 



