ALTAZIMUTH INSTRUMENT. 



357 



The Meridional transits selected for publication are (1) all stars observed 

 with the Moon on the meridian ; (2) stars observed in connection with Altazi- 

 muth observations; (3) stars observed in connection with Lord Lindsay's 

 chronometric expedition from the Mauritius. The mean determinations of 

 the transit clock-error are given in Table V., incorporated in Table IV. The 

 relative personal equations of the observers cannot be determined from the 

 observations. 



OBSERVATIONS OF ZENITH DISTANCE. 



The Altazimuth instrument at Point Venus was exactly similar to that 

 used at Honolulu, described in Part I., page 18. The values of the gradua- 

 tions on the upper and lower zenith distance levels were 30 and 25 to one 

 minute of arc respectively. 



The system of wires remained perfect throughout the observations. 



No imperfect vertical transits have been used. 



The Zenith Point corresponding to the Mean of the Wires was l" - 7 greater 

 than that corresponding to the center wire. 



The Mean Corrections to the reading of the vertical circle for runs of the 

 four micrometer screws for 100" were as follows : 



zz 2 



