( 446 ) 



lite if it is at the position g, one of the other three sateUites being 

 then at one of the points of intersection already mentioned. 



Each of the satellites mi,^ht thns produce six different eclipses; 

 if however we compute the radii of the umbra for the positions of 

 the other satellites we are led to a negative value in some of the 

 cases. This means of course that the vertex of the cone of the 

 umbra does not reach the other satellite. 



If for the radii of the satellites we adopt the Milues mentioned in 

 the first part of this communication, diminished however by the 

 amount of the irradiation, it appears that a total eclipse is only pos- 

 sible in two cases. Ill,; may cause a total eclipse of 1I„ and In ; If 

 may nearly produce such an eclipse of 11/; If the shadow does not 

 reach the other satellite then an inhabitant of the latter would see 

 an annular eclipse of the Sun. 



This case presents itself 



for the shadow of I„ in respect to IV/- . 



„ II„ „ „ „ III/ and IV/, 



mlV/- 

 „ IV„ „ ,, ,, 11/ and III/-. 



In the tifteen remaining cases there may be a partial eclipse. 



It need hardly be said that this case can only present itself if, at 

 the time of heliocentric conjunction, the difference of the heliocentric 

 latitudes {y' — y), is smaller than the sum of the radii. In computing 

 however the occultations observed by Messrs Fauth and Nijland it 

 appeared that this difference in latitude, according to the tables of 

 Damoiseau, is sometimes slightly greater. The latitudes found by these 

 tables are therefore not entirely trustwoi'thy. For this reason we in- 

 cluded all the heliocentric conjunctions between 1 April and 20 May 

 1908 (both dates inclusive). 



The preparation for the computation, viz the drawing of the orbits 

 of the satellites is the same as for the computation of the geocentric 

 conjunctions (see 1^"^ part). First however the epochs of the helio- 

 centric superior conjunctions must be derived from the epochs of 

 the geocentric superior conjunctions taken from the Nautical Almanac 

 by the aid of the hourly motions of the satellites and of the angle 

 G, i.e. the angle Earth — Jupiter — Sun. Furthermore, the jovicentric 

 mean longitudes should be corrected for their equations and pertur- 

 bations and diminished by S. i. e. the heliocentric longitude of Jupiter, 

 instead of by S — G which is its geocentric longitude. 



Of the arguments N°. 3 need not be computed; for this argument 

 only serves, combined with 1, for the computation of thejovicenti-ic 



