affected by the Earth. 257 
Ist. The position of the nodes cannot be shifted by the earth’s 
action more than a degree or two in half a million of years, 
Without attempting nice determinations, in the absence of data 
entirely explicit, it is sufficient to observe that the few expres- 
sions above formed in (F) show such a balance of opposite effects 
as must leave the meteors which pass at three to five millions of 
miles on every side of the earth neutral in respect to advance or 
tetrogradation,—so that a cylinder of many millions of miles 
“diameter and length of axis, although retrograding in the parts 
Within a certain limit as just mentioned and a vancing in the 
Parts beyond it, would as a mass remain not appreciably dis- 
turbed in either respect. 
_2d. An effect of another kind would however become appre- 
clable in a separation into more or less advanced assemblages of 
orbits with constituent meteors retaining in various degrees a 
yommon amount or direction of disturbance. Thus a belt of or- 
bitsin planes parallel and contiguous to Est will retrograde less 
than such as group themselves in planes parallel and near to the 
The latter will be occupied by 
mn the lapse of ages by these two classes of orbits under the gen- 
= planetary influences. 
ae approach. : 
4th. The wa lanter disturbance is sufficient to affect the me- 
teors’ perihelion distances by many millions of miles and to ex- — 
the ring to 
“8 which are similarly affected in respect of radiant positions. 
Ax. Jorn. Sci.—Szcoxp Serres, VoL. XXXII, No. 9&—Mance, 1862, 
