37 



in which they delimited what is now the Colonial Empire 

 of Great Britain. The one striking exception is that of the 

 island of Tahiti, and there it should be noted that the French 

 Government did not rind it necessary to supersede Cook's 

 charts of the Society Group by more recent and elaborate 

 surveys until 120 years after his death. 



Early in the Restoration period English clockmakers 

 had achieved pre-eminence in their art, and THOMAS TOMPION 

 (1638-1713), " the father of English watchmaking," who had 

 made the first two clocks possessed by Flamsteed, was the 

 acknowledged leader in horology. He was followed by his 

 nephew, GEORGE GRAHAM (1673-1751), whose great skill 

 and ingenuity were directed chiefly especially in the later 

 part of his life to astronomy and astronomical instruments, 

 and especially to the production of a perfectly astronomical 

 clock. After the success of Harrison's chronometer had been 

 established, the English chronometer-makers at the end of 

 the 1 8th century, JOHN ARNOLD (1736-1799), THOMAS EARN- 

 SHAW (1749-1829), and others, created an equal reputation 

 for their branch of horology ; and, a little later on, the care 

 of the chronometers for the use of the Royal Navy became 

 an important part in the routine of Greenwich Observatory. 



Great as Maskelyne's main work was, he was able to devote 

 much time and thought to other important problems the 

 determination of the distance of the sun, through observations 

 of the transits of Venus hi 1761 and 1769 ; and of the density 

 of the earth, by noticing the deviation produced in the plumb- 

 line by the attraction of the mountain Schiehallion. 



JOHN POND (1767-1836), who succeeded him, was a skilful 

 observer, and, in 1833, brought out a standard catalogue of 

 1,113 stars, at that date the fullest of any catalogue prepared 

 on the same scale of accuracy. His chief merit was the 

 introduction of several new instruments and the multipli- 

 cation of observations of stars with different instruments 

 and under different conditions. 



Pond retired in 1835 and was succeeded by GEORGE 

 BIDDELL AIRY (1801-1892). Up to his time the problem of 

 navigation had been dominant ; during his time and onward 

 other inquiries, arising naturally out of the actual work of 

 the Observatory or linking themselves on to it, have claimed 

 an ever-increasing attention. Previous to Airy, the Astro- 

 nomer Royal had himself practically been the Observatory, 

 and such assistants as he employed might rather be described 

 as his personal secretaries and clerks. Under him the insti- 

 tution developed slowly but steadily into a distinct Govern- 



