358 TRANSIT OF VENUS, 1874. RODRIGUEZ. POINT VENUS. 



On November 13 the object-glass of microscope B, with its cell, was 

 discovered to be broken away from the body of the microscope. It was 

 effectively repaired with cement. The observations of November 12 and 13 

 have, in consequence, been rejected. An examination of the differences of 

 the means of opposite microscopes, before and after November 13, seems to 

 show that the accident was discovered soon after it occurred. 



A mercurial barometer, by Messrs. Home and Thornthwaite, which had 

 been tested at Greenwich and found to have no appreciable error, was sus- 

 pended inside the Altazimuth hut. A verified thermometer was placed 

 outside on the S.W. side. The thermometer attached to the barometer 

 generally read 3 higher than the external thermometer ; but it cannot be 

 thence inferred that the temperature within the hut was higher to that extent 

 than the external temperature, the attached thermometer not having been 

 verified. 



Satisfactory comparisons of the Altazimuth Clock, Dent 2014, with the 

 Transit Clock, Graham 2, were made on 56 days. 



The LATITUDE of the ALTAZIMUTH PIER. 



Numerous observations for co-latitude were made on 42 days, on stars 

 very near to the meridian, at zenith distances from 10 to 65 ; in one 

 instance at 75. The mean results are 



C I If 



From 5g stars North of the Zenith, Co-latitude = 70. 19. 38'2 S. 

 28 South 70.19.37-6 



The declinations of the northern stars depend upon observations at Green- 

 wich ; those of the southern stars upon observations at Melbourne and at the 

 Cape of Good Hope. 



The adopted latitude of the Altazimuth pier is 19. 40'. 22"-l S. 



On the LONGITUDE of POINT VENUS. 

 (1.) From tJie Observations of the Moon on the Meridian. 



The observations have been reduced as described in Part I., page 22. The 

 results for longitude are exhibited in the usual form in Table VI., from which 

 are obtained the following means : 



