MERIDIAN TRANSITS, AND PERSONAL EQUATIONS. 



409 



when there has been an interval of several hours between the observations of 

 the clock and circumpolar stars. The second place of decimals in the value 

 of " Clock Slow " will generally have no significance. 



The observers are indicated, where required, by the initials 



P 



C - 

 CO 

 G - 



ws 



BS 



Mr. Perry. 

 Lieutenant Coke. 

 Lieutenant Corbet. 

 Lieutenant Goodridge. 

 Mr. Sidgreaves. 

 Mr. Smith. 



EELATIVE PERSONAL EQUATIONS OF THE OBSERVERS. 



Although there are not many observations of transits of stars by two 

 observers on the same night, the steadiness of the clock-rate admits of 

 approximate values of the relative personal equations being obtained by 

 comparing one day with the next.. Nearly the whole of .the azimuths of the 

 Moon were observed by Mr. Sidgreaves, with local time obtained by another 

 observer with the transit instrument. Mr. Sidgreaves' custom of observing 

 the azimuth of a star with every observation of azimuth of the Moon 

 practically makes the latter independent of small errors in the local time ; 

 but as the habits of these observers appear to differ in a very unusual 

 manner, the approximate differences have been investigated. In the following 

 table the equation P G = + O s> 06 signifies that P makes the clock O06 

 more slow than does G. Every one of these determinations is affected by 

 the uncertainty of the collimation zero, and nearly every one of them by 

 uncertainty of the azimuth error. The second place of decimals must, of 

 course, be regarded as of no significance. 



3 G 2 



