aise 
1872.] 411 [Chase. 
action of allthe planets, except Jupiter, upon the Sun’s surface. Accord- 
ing to the values ey in Norton’s Astronomy, (1—3)x(Smd+3mB, 
2,8, dy kh, 6, VU) 4.422; 4.485 4.422—1.015. 
The closeness of ae harmony, pointed out by Kirkwood, between the 
Woltfian and Mercurial cycles, is very interesting. In some respects the 
position of Mercury is more nearly pivotal than that of either of the 
other planets. Its centre of explosive oscillation, relatively to the Sun, 
is near the limit of the Sun’s possible atmosphere. (4.887 
365.2564 +-25.187—=1.036. Its mean radius vector (.8871) is not much 
greater than the radius of the centre of oscillation (.3333) of the Earth’s 
disturbing action upon the Sun. That centre of oscillation is, in its turn, 
near the centre of the counterpoising moments of inertia of the Sun and 
Qo 
the planetary system. For Sm(d—.3333)?+-Sim—9.0776? ; 759.46 +-9.07762 
=.9294 5 .3333+.8294—1.012. It may be well to observe that this 
approximation is nearly identical with the one above noted (1,015) be- 
tween the virtual centre of gravity of the Jupiter-disturbing planets, and 
the Sun-spot disturbance-perihelion, 
In order to form an estimate of the extent, to which circumstances 
favoring the generation or disturbance of ethereal waves affect the amount 
of spotted surface, I would suggest a preliminary examination of ob- 
servations with especial reference to the following planetary configura- 
tions : 
1. When the Sun is near the linear centre of oscillotion (3) of two 
planets in heliocentric opposition : ¢. y., near the opposition of Mercury 
and Venus, especially if Mercury is about 60° from perihelion ; of Venus 
and Mars, when Mars is about 40° from perihelion ; of Jupiter and Saturn, 
eee Saturn is near aphelion ; of Saturn and Uranus. 
When one of two planets in heliocentric conjunction is near a linear 
centre of oscillation of the longer radius vector : ¢. g., near the conjune- 
tion of the Earth and Mars; of Mars and Mercury, if Mars is near peri- 
we 
ox 
helion and Mercury near aphelion ; of Jupiter and Mars, if Mars is near’ 
aphelion; of Jupiter, Saturn and Uranus, (the centre of gravity of 
Jupiter and Saturn being at about 3 of the distance from Uranus to the 
Sun); of Saturn and Neptune, when Saturn is near aphelion ; of Uranus 
and Neptune 
3. When one of two planets in heliocentric conjunction is near a centre. 
of explosive oscillation (3): @. g., near the conjunction of Mercury and 
Venus, if Mercury is at somewhat more than its mean distance from the 
Sun ; of Mercury and the Earth, if Mercury is near aphelion ; of Mercury, 
Venus, and the Earth or Mars; of Jupiter a es Saturn. 
ATHEREAL OSCILLATION, on PRIMORDIAL MATERIAL, 
FORCE. 
By Puirny EARLE Cuase. 
(Read before the American Philosophical Society, July 19, 1872.)) 
In any explosive or other analogous action along a given diameter, 
cardinal points occur at } radius and § radius (—the distance from 
