100 



THOUGHTS ON THE INFLUENCE OF ETHER 



ETHRE. ITS EELATIONS TO PEEIODICAL SHOOTING STAES. 



With the seasons of warmth, whose causes T have endeavored to determine, there seems 

 to be allied by a nice coincidence in time, a phenomenon of a very different character. I 

 refer to periodical shooting stars. 



The first of these phenomena in the order of the year, appears on or about the 10th 

 August, a time which corresponds exactly with the mean occurrence of the dog days. 



The other exhibition is observed on the 12th November, and to show the closeness of 

 the coincidence in time with the Indian summer, we may call to mind that this season in 

 the south of Europe is known as the summer of St. Martin; the festival of which saint is 

 celebrated on the 11th November. 



Shooting stars being one of the most beautiful and striking features of night, men have, 

 in all ages, made their origin and nature a subject of speculation. 



An intelligent compiler has classified the various explanations offered upon the subject, 

 into the following five hypotheses : the atmospheric ; the volcanic ; the planetary ; the 

 lunar ; and the nebular.* 



This classification is imperfect, as it docs not include Professor Olmstead's scheme of a 

 nebula revolving round the sun once in six months, and meeting the earth on the 12th 

 November;! nor tnat adopted by Sir John Herschcl, in 'which a broken stream or annulus 

 of meteors is encountered by the earth in a certain part of its orbit: the breaks in the 

 annulus corresponding with the omissions of the exhibition. 



I stated my objection to Professor Olmstead's hypothesis when treating of the zodiacal 

 light, in its rcqiiiring a precise coincidence in the periodic time of two bodies moving in- 

 dependently of each other. 



The explanation of the broken stream of meteors has received the support of many of 

 the most distinguished savants of Europe, among others, of Poisson, Arago, and Von 

 Humboldt. It is bold, and to my view arbitrary, as it has no analogies with known astro- 

 nomical facts to give it probability; nor is any other phenomenon of nature explained by 

 it. It appears, too, that this hypothesis does not exhibit that ingenuity which we look 

 for in a scheme supported by such distinguished men, for Sir John Herschcl says : " We 

 need not suppose the meteoric ring coincident in its plane with the ecliptic. "X This debars 

 its defenders of the ability to account for more than one exhibition in a year, unless they 

 occurred at precisely opposite seasons. 



* Lardncr's Lectures on Science and Art, vol. i, p. 461. 

 f American Journal of Science and Art, vol. xxix, p. 376. 

 X Outlines of Astronomy, chapter xvii. 



