198 W. A. Norton on Molecular Physics. 
tioned, dependent upon their masses, distances, and annual mo- 
tions; which gives results in close correspondence with the results 
of the observations made between 1826 and 1848 (Astr. Nachr., 
No. 1181). He has more recently extended his investigations, 
so as to include, but with less certainty, a much longer period. 
The epochs of maxima and minima, from 1750 to 1856, are 
given in the following table, to which we have added the corres- 
ponding mean heliocentric longitudes of Jupiter and Saturn; the 
two planets upon which the varying number of spots developed 
d . 
uring a year, chiefly depend. 
oe of Jupiter. Saturn. | A ma upiter. Saturn. 
° 
1750°0 4°42 231°6 1755°7 177°4 801-4 
1761-5 853°4 12 1766-5 145°1 
17700 2514 116°2 1775°8 67°4 187'3 
1779°5 179°7 232-4 17848 340°5 2973 
1788°5 92° 342-4 1798°5 36°3 104°9 
18040 203°3 172°0 18105 40°5 251°5 
1816°8 231°8 828°5 1823°2 66°0 46°83 
1829-5 2572 123-9 1833 27:7 176-4 
1887-2 1380-9 218:0 18440 337° 301-2 
1848-6 116-9 357°5 1856°2 847°6 
into account. If we separate the positions that fall in the tw? 
halves of the ecliptic, lying on opposite sides of the line from 
253° to 73°, we bot the average positions 162°, and 333°. If 
we include the first two epochs the latter average becomes 349 - 
‘The average position of hata at the epochs of maxima, W4$ 
236°. eo one 
If we now direct our attention to the first two epochs of max" 
ima, we shall perceive that Jupiter was in that part of the eclip- 
tic in which his ordinary action is the least; and if we refer to 
the first two epochs of minima, it will be seen that he was in, 
