- 
298 Scientific Intelligence. 
The period is about 11 years, the number of our year giving an ill- 
defined mark. eriod by a primary cause oscillates by secondary 
causes. The revolution of Jupiter, the largest planet, is 11°86 years, 
There is affinity in these numbers. The maxima occurred in 1828, 1837 
and 1848; another draws near; farther off, six periods correspond to six 
revolutions of Jupiter; but I may be mistaken, and by a constant accele- 
ration seven periods may take place. When we try to combine the days 
of observation, the number of spots and of spotless days, we find the in- 
crease and decrease to be in a slow ratio before and after the maximum, 
the decrease and increase in a rapid ratio before and after the mink 
mum, a coincidence with the requirements of elliptic motion. 
In 1828, 1837 and 1848 occurred the maxima. In 1827, 1839, 
1851, 1862, Jupiter passes 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 “increases 
e envelop; the aphelion condenses it, introducing a rapid alternation 
of precipitation and evaporation; the mass is thereby allowed to descend 
and meet in the equatorial regions, and the temperature 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 is a number of other planets; if we abstract from the far 
e 
ponding to the aphelion of Jupiter) in advance of its perihelion, : 
number of spots was considerably less than in 1837 or 1848. fs 
elions, and 
the greatest number of spots occurred before 1839. The reason . si 
sition 
pe seal 
r of th 
yerage dis 
tance diminished, the angular velocity of the greater augmented, whereat 
: , —o A § 5 § he latter half 
pretty near coincides) advancing to its aphelion, and the max 
e delayed till near that time. There is here a coincidence wt iod, 
aphelion of Jupiter, but the maximum is in itself small. The next pe 
1874, is brought down to. 1872. ue 
A relation between the “spots” and the oscillations of magne” 
suspected ; it must exist. The planets must influence the magnets’? 
the effect from Jupiter on the earth must be large, as the | 
. 
umes revolving, passes at one time between the sun and th 
atter twelve 
at planet in 18 pe 
ii i 
