( 325 ) 



Sum of the diameters Sum of the radii 

 . . O'-llO 0'-055 



. . 143 0715 



. . 134 067 



. . 137 0685 



. . 128 0-064 



. . 161 0805 



For the mean radii vectores we will take two figures more than 

 did Damoiseau in his tables, and we will adopt for the purpose the values 

 found by Souillart in Damoiseau's papers, (Souillart, second paper, 

 Mémoires présentés par divers savants a I'Academie des Sciences, 

 Tome XXX, 2™« Série, 1889 ; p. 10) '). 



I 60491, 



II 9 6245, 



III 15-3524, 



IV 270027. 



The result of our computation is, that the time between the first 

 contact and the central occultation is : 

 for I and II I and III I and IV II and III II and IV III and IV 



1^-324, l'i-245, 111103, 2i>-263, li'-774, 3^725; 

 between the central occultation and the second contact: 



1^204:, J'>161, li>059, 21^190, 1^-767, 31^-725, 

 therefore in all 



2''-528, 2i'-406, 2''162, 4''-453, 3i'-541, 7''-450, 

 or 



2h32m^) 2''24'", 2^10'", 4i>27"S 3^32-", 7^27"^ 



Still even these numbers do not represent the maximum of the 

 time during which the two satellites may be seen as a single body. 

 For we can imagine the case that the shortest distance becomes 

 equal to — (r + r'), i. e. that between two central conjunctions there 



1) According to Souillart, Damoiseau derived these numbers in the follo^Ying 

 way: He adopted the mean distance of IV, in accordance with Pound's determi- 

 nation = 496"-0, and took 18''-37 for Jupiter's semidiameter, so that, by division 

 riv = 27-00102834. The mean distances of the other satellites were then derived 

 from the sidereal periods by the application of Keppler's third law. But to these 

 mean distances he added the constant terms produced in the radii vectores by 

 the perturbing force. 



I beg leave to remark that 496"0 : 18''-37 is not 27-00102834 but 27000544366. 

 Happily the 4'!', 5"\ 6i", 7"' and S'h f,gure have no appreciable influence on our 

 computations, nor probably on those of Souillart. For the rest the 2"'i appendix, 

 further below, may be consulted on such numbers of many decimals. 



2) On June 4, 1908, such a conjunction must take place according to our com- 

 putation. Vide the table further below. 



