ASTRONOMY AND METEOROLOGY. 375 



(Mr. Francis Bradley), a third drew from us both a simultaneous excla- 

 mation. This remarkable consecution of a phenomenon against which 

 there were so many chances, and against the repetition of which x in 

 such a brief space, the chances were so many millions of millions, sat- 

 isfied me that multitudes of undiscovered meteors were in play over 

 us, but for some reason not seen except when their flight was directed 

 exactly to the observer. If this was the fact, a telescope truly pointed 

 to the radiant, would have discovered yet more stationary points of 

 brightness. Such an attempt, if successfully made, and ascertained to 

 be ordinarily practicable, would realize this remarkable advantage, 

 that, by employing the telescopes of graduated instruments, our radi- 

 ant positions might be defined with certainty, and with some rude ap- 

 proach, at least, to astronomical accuracy. 



For any considerable advance upon our present knowledge of me- 

 teors and meteoric rings, we are clearly dependant upon accurate 

 systematic and concerted observations. Even a casual observation 

 of the principal meteor of a late meteoric display, made coincidently, 

 although without concert, by observers at New Haven and at Bur- 

 lington, N. J., has seemed to prove, even upon the rudest attention, 

 that the meteors of November and the meteors of August are inde- 

 pendent and distinct in their origin or source. The circumstance 

 that upon certain definite days in August of each year, and in No- 

 vember of many years, observers will surely be rewarded with abun- 

 dant opportunities and subjects for their attention is, of itself, one 

 inestimable encouragement to concert and assiduity. 



Professor Twining ventures the opinion that, beyond a definite 

 limit of the earth's atmosphere proper, there exists a secondary or 

 external atmosphere, possibly of aqueous vapor; that in this external 

 medium the shooting stars become visible, and that a knowledge of 

 its upper limit may be obtained by considering and comparing the 

 upper limit of the meteors' paths. It has long been his suspicion, to 

 say the least, that some of the irregularities or specialities in meteors' 

 flights are to be explained by their encountering a sudden change of 

 medium from a secondary or exterior atmosphere to the atmosphere 

 proper. 



Prof. H. A. Newton, in a communication to Silliman's Journal, 

 Nov., 1861, on the " August ring of meteors," says : 



The well-established fact that the meteors of August 9-11 move in 

 paths which, produced backward, pass through a small region of the 

 heavens, and that this region of emanation remains the same, or 

 nearly the same, from year to year, implies, 



1st. That the individual meteors are cosinical bodies. 



2d. That they are permanent members of the solar system revolv- 

 ing about the sun in elliptic orbits. 



3d. That the direction and velocity of the relative motion, and, 

 therefore, of the absolute motion, of the individual bodies are nearly 

 the same. 



4th. That the whole group form what may be considered a ring, 

 or disc, around the sun. The region of emanation has not a great 

 length in the great circle through "it and that point of the heavens 

 to which the earth is moving. Hence the velocities of the individual 

 meteors of the same year and of different years are nearly the same. 



