38 



ment department, with an organised and responsible staff, 

 recognised members, like their chief, of the established 

 Civil Service. But throughout the great development 

 which has taken place in the Observatory since 1835 the 

 essential continuity of the institution has always been borne 

 in mind. As Airy himself expressed it, " The Observatory 

 was expressly built for the aid of astronomy and navigation, 

 for promoting methods of determining longitudes at sea, 

 and (as the circumstances that led to its foundation show) 

 more especially for the determination of the moon's motions. 

 All these imply, as their first step, the formation of accurate 

 catalogues of stars, and the determination of the funda- 

 mental elements of the solar system. These objects have 

 been steadily pursued from the foundation of the Observa- 

 tory." It is to this recognition of the essential continuity of 

 Greenwich Observatory that its high reputation is chiefly 

 due, winning from SIMON NEWCOMB (1835-1909), the great 

 American astronomer, the striking comment : " The most 

 useful branch of astronomy has hitherto been that which, 

 treating of the positions and motions of the heavenly bodies, 

 is practically applied to the determination of geographical 

 positions on land and sea. The Greenwich Observatory has, 

 during the past century, been, so far, the largest contributor 

 in this direction as to give rise to the remark that, if this 

 branch of astronomy were entirely lost, it could be recon- 

 structed from the Greenwich Observations alone." 



Airy was succeeded in 1881 by his Chief Assistant, W. H. M. 

 CHRISTIE, who held office for 30 years, and was followed 

 by the present Astronomer Royal, FRANK W. DYSON, who 

 had already held the position of Chief Assistant at Greenwich 

 from 1894 to 1906, and had been Astronomer Royal for 

 Scotland from 1906 to 1911. The rule of these three 

 Astronomers Royal cover the modern period of the Obser- 

 vatory. 



Perhaps the readiest way of gathering a general impres- 

 sion of the activities of Greenwich Observatory will be to 

 examine one of the Annual Reports, presented by the Astron- 

 emer Royal to the official Board of Visitors on the occasion 

 oi the annual visitation. This Board, first established in 

 1710, received its present constitution in 1830, and represents 

 the Royal and the Royal Astronomical Societies, the two 

 Universities of Oxford and Cambridge, and the Admiralty, 

 of which the Observatory is a department. The last Report 

 presented before the outbreak of the war, namely, that read 

 on June 6, 1914, may conveniently be taken as indicating 



