ASTRONOMY AND METEOROLOGY. 391 



1837, and 1848 ; another draws near ; further off, six periods corre- 

 spond to six revolutions of Jupiter; but I may be mistaken, and by a 

 constant acceleration seven periods- may take place. When we try 

 to combine the days of observation, the number of spots and of spot- 

 less days, we find the increase and decrease to be in a slow ratio be- 

 fore and after the maximum, and the decrease and increase in a rapid 

 ratio before and after the minimum, a coincidence with the require- 

 ments of elliptic motion. 



In 1828, 1837, and 1848 occurred the maxima. In 1827, 1839, 

 1851, 1862, Jupiter passed its aphelion. The first numbers coincide. 

 The frequency of spots corresponds to the aphelion of Jupiter. The 

 pressure at the perihelion, as my theory supposes, expands and in- 

 creases the envelope ; the aphelion condenses it, introducing a rapid 

 alternation of precipitation and evaporation ; the mass is thereby al- 

 lowed to descend and meet in the equatorial regions, and the temper- 

 ature is there increased. The numbers do not all coincide. But, 



(1.) Do the maxima by groups of spots correspond to the greatest 

 area and darkness ? No days were spotless in 1829, 1838, and 1839; 

 all those years produced spots of largest dimensions. 



(2.) There are a number of other planets; if we abstract the 

 far and s!ow, and the near and rapid small ones, the second central 

 planet remains as the principal disturber. In 1827 Saturn was 10 

 (corresponding to the aphelion of Jupiter) in advance of its peri- 

 helion, and the number of spots was considerably less than in 1837 or 

 1848. In 1839 Saturn was 23 from its aphelion, advancing toward 

 it. During the preceding years both planets advanced together 

 towards their aphelions, and the greatest number of spots occurred 

 before 1839. The reason of this anticipated maximum becomes obvi- 

 ous when we consult the position of the two aphelions. When the 

 two planets draw near each other, the attractive force of the greater 

 diminishes the spot-producing power of the smaller, the combined 

 pressure on the sun is increased, the average distance diminished, the 

 angular velocity of the greater aug-mented ; whereas both planets ad- 

 vance in 1837 towards their aphelions in the latter half of the semi- 

 orbits, but differ still about a quadrant in length ; their spot-producing 

 effect culminates ; they exercise the least pressure, the least repulsion, 

 on the interior sun. In 1851 Saturn was 60 from its perihelion, ad- 

 vancing towards it; beyond 48 its effect diminishes, the spot-produc- 

 ing effect of Jupiter still advancing to its aphelion. In 1862 Saturn 

 will be 82 from its perihelion (in 1857-58 the time of the two peri- 

 helions pretty nearly coincides), advancing to its aphelion, and the 

 maximum will be delayed till near that time. There is here a coin- 

 cidence with the aphelion of Jupiter, but the maximum is in itself 

 small. The next period, 1874, is brought down to 1872. 



A relation between the "spots" and the oscillations of magnets is 

 suspected ; it must exist. The planets must influence the magnet- 

 ism. The effect from Jupiter on the earth must be large, as the latter, 

 twelve times revolving, passes at one time between the sun and that 

 planet in its perihelion, and then in its aphelion. The earth is now 

 pressed, now elated, its envelope now expanded, now condensed, 

 between these two rotating balls, magnets, or voltaic piles, or weights, 



