NO. 6.] 



INTRODUCTION. CHRONOMETERS. 



XXXIII 



is the relative velocity of the Satellite, expressed in parts of a, and as r = b . a, 



1 



w = 



b .t 



will give w, k and x in parts of the Satellite's radius. 



If S is the time of synodic revolution of the Satellite, /? is determined by 

 the equation 



The following Table contains these several quantities which formed the 

 basis of the calculation; it gives 10 w instead of w because it was convenient 

 to multiply both sides of equation (6) by 10. Barnard's value of Jupiter's 

 equatorial diameter at the distance 5.20 is 38".E 



The projected velocity k was calculated for the three inner Satellites at 

 intervals of about half a year (a whole number of synodical revolutions in 

 every case) from 1893.0 to 1898.5 ; for Sat. IV whose latest period of eclipses 

 began in 1895 it was calculated with intervals of 67 days (4 synodical revolu- 

 tions) from 1895.2 to 1897.1. The values which are given below were plotted 

 on cross-ruled paper and curves drawn, from which the value could easily be 

 taken out for any given eclipse. The Table gives 10 k. 



Sat. I. 



Sat. II. 



