356 



TRANSIT OF VENUS, 1874. RODRIGUEZ. POINT YENUS. 



MEAN PLACES, for 1874 '0, of the STARS observed at POINT VENUS for 

 AZIMUTH ERROR, as given by Mr. STONE.* 



The Catalogue of 78 Stars was brought up to 1874, January 1, and the loga- 

 rithms of a, b, c, d and a, V, c, d' computed, before the Expeditions left England. 



The Transit clock was originally constructed by Graham for the Royal 

 Observatory. It was put into good order, and supplied with a cylindrical 

 zinc-and-steel compensated pendulum by Messrs. E. Dent arid Co., and tested 

 for many months at the Royal Observatory before the departure of the 

 Expedition from England. At Rodriguez its rate (Table V.) was not so 

 regular as it had been during the testing at Greenwich. It was mounted 

 upon a solid wooden tripod, resting upon the rock, and nowhere touching the 

 floor of the observatory. 



The stars observed for clock-error were taken generally from the list in 

 use at the Royal Observatory, Greenwich. The Mean Right Ascensions have 

 been brought up to the beginning of the year from the Greenwich Catalogue 

 of 2760 Stars for the Epoch 1864. The reduction for the day has been taken 

 from the Nautical Almanac for all stars found in that work. 



The Meridional transits (Tab. IV.) have been reduced as described in 



* Places of eight close Southern Polar Stars, Eoyal Observatory, Cape of Good Hope, 1874, 

 and Catalogue of 78 Stars near the South Pole, Monthly Notices, R.A.S., XXXIII., 55. 



