158 Intelligence and Miscellaneous Articles. 



determination of the point which reached me was from my son 

 Mr. Hubert Airy, who had occasion to walk several miles between 

 five and six o'clock in the morning of the 14th (Nov. 13, 17 h to 18 h ), 

 and carefully observed a considerable number of meteors, the inter- 

 section of whose paths he determined accurately ; subsequently I 

 received the chart of Mr. Alexander Herschel, made several hours 

 earlier, and observations of other persons at different hours ; and all 

 agreed in fixing on the point which I have specified as the centre 

 of divergence. 



It will readily be understood that this divergence from one point 

 is merely an effect of perspective, that the point of divergence is, in 

 fact, the point opposite to what is usually known as the '* vanishing 

 point." It is, of course, theoretically possible to imagine an ex- 

 plosive point in space so changing its position as to produce effects 

 like those which were seen ; but no person, I suppose, will really 

 maintain that explanation against the simple one that the meteors, 

 for the most part, retain a nearly unvaried relative position among 

 themselves, and that the effects observed were produced by the 

 relative movement of the Earth and the collection of meteors. 



I assume here that the resistance of the air produced no remark- 

 able change in the apparent paths of the meteors ; which assump- 

 tion appears to be justified by the agreement of the diverging-points 

 when far from the meridian and when near the meridian. The same 

 agreement justifies us in thinking that the course of the meteors was 

 not much disturbed by the Earth's attraction — a consideration, 

 however, which in future must not be put out of sight. 



I ought in strictness to have ascribed the observed effects to the 

 relative movement of the point of observation and the collection of 

 meteors ; but this differs from the other by an extremely small 

 quantity, and if the corresponding correction were applied, it would 

 diminish the angle which I am about to mention by an insignificant 

 fraction of a degree. 



Now, if the meteors had been stationary in space, they would have 

 appeared to diverge from that point in the celestial sphere towards 

 which the Earth's motion was directed. That point is very nearly 

 the point on the ecliptic 90° behind the Sun's apparent place, or is 

 in longitude 141° nearly. The point of divergence did not very 

 much differ, in longitude, from the point thus found ; but it was 

 north of the ecliptic by about 1 1°. It follows from this that the 

 meteors were not stationary in space. They had not much motion 

 towards or from the Sun ; but they were moving perpendicularly to 

 the plane of the ecliptic, from north to south, with an absolute 

 velocity nearly one-fifth part of the velocity relative, to the Earth in 

 the direction of the Earth's motion. 



We have no information as to the real value of their velocity 

 relative to the Earth in that direction ; and every subsequent stage 

 of investigation is therefore imperfect. 



Let V be the velocity of the Earth in its orbit, and v the velocity 

 of the meteors in the same direction (considered as perpendicular to 

 the Earth's radius vector), the relative velocity of the meteors in 



