scheme for photographing the heavens. The work was to 

 oe divided between 18 Observatories of different nationalities, 

 of which number Great Britain and her Dominions in the 

 Southern Hemisphere have furnished six. It was planned 

 to result in a photographic chart extending to the I4th magni- 

 tude and probably embracing some 40 millions of stars, 

 and to furnish a catalogue, made from measures of the photo- 

 graphs down to the nth magnitude, which would probably 

 include between two and three million. 



Referring again to the Astronomer Royal's 1914 Report, 

 we find that 16,423 transits and 16,455 circle observations 

 were made within the year by means of the transit circle, 

 beside many hundred determinations of the adjustment of 

 the instrument itself. The bulk of these observations were 

 for the completion of a catalogue of all stars down to the gth 

 magnitude in brightness in the zone lying between 24 and 

 32 north of the equator. This catalogue was to contain 

 the places of some 12,400 stars in the zone which has been 

 assigned to the University of Oxford in the great international 

 scheme for photographing the entire heavens, the places 

 of the stars being intended to afford reference points for the 

 Oxford plates. The " probable error " of a single observa- 

 tion of a star is ^ih of a second of time in Right Ascension, 

 that is in the determination of the time of the transit of a 

 star across the meridian, and less than a second of arc 

 in the determination of the distance of a star from the North 

 Pole of the heavens. 



The Observatory of Greenwich, like that of the Oxford 

 University, took part in the great international scheme, 

 and the region assigned to it was that round the North Pole 

 and extending 26 from it. Hence one of its most important 

 instruments of late years has been the Astrographic Telescope, 

 a double-barrelled instrument, one barrel being the photo- 

 graphic telescope of 13 inches aperture and focal length of 

 ii feet 3 inches, and the other a guide telescope of 10 inches 

 aperture, the whole having been designed and constructed 

 by HOWARD GRUBB of Dublin. The main work of the As- 

 trographic Telescope has been completed for some years, 

 and it is now devoted to subsidiary researches of a minor 

 character, those reported in 1914 relating partly to the 

 standardisation of the magnitudes of the stars shown on 

 the photographs. 



The original method proposed for ascertaining the longi- 

 tude at sea required that the motions of the moon should be 

 so thoroughly known that its place at any required epoch 



