﻿and Acoustic Phenomena attending the Fall of Meteorites. 2G3 



observations of several meteors, and his discovery of the spectrum- 

 line of sodium as distinct as in the spectrum from a gas-flame of 

 a Bunsen's burner or of a monochromatic flame richly fed with 

 common salt, together with his observations on the forms and 

 modifications of the luminous remains of meteors, deserve special 

 attention, as they seem to confirm the supposition of a gaseous 

 envelope forming around the progressing nucleus. Mr. Her- 

 schel says*, "Each new acquisition of knowledge, however un- 

 foreseen may be its origin, tends to support the theory of Chladni, 

 and to confirm the belief that shower-meteors and shooting- 

 stars are actually aerolites of small dimensions. In whatever 

 manner aerolites and shooting-stars are related to each other in 

 their astronomical and other peculiarities, they will evidently 

 require a vast number of future experiments to unfold their real 

 source." The meteor telescopically observed by Mr. II. Christ 

 at Basle, June 11, 1867, 8.30 to 9 p.m., and pursued in its 

 further course, N.W. to S.E., by Professor E. Hagenbach-Bischof 

 at Basle and by M. de Fonvielle at Paris, excited likewise a great 

 deal of interest. 



14. Professor J. J. Omalius d'Halloy, in the eighth edition of 

 his Precis elementaire de Geologie, has devoted a special chapter 

 to meteorites and the phenomena attending their apparition, 

 in which he briefly expounds von Haidinger's views on the 

 subject. He says (p. 118), "4s to the light manifested by 

 bolides in their course through the atmosphere, and the vitrifi- 

 cation undergone by their crust, M. Haidinger explains both 

 these circumstances by the development of heat and light re- 

 sulting from the compression of the air in consequence of the 

 rapidity of the meteors- falling towards the terrestrial surface; 

 and he ascribes the detonations attending their fall to the irrup- 

 tion of the ambient air rushing into the vacuum left by the 

 passage of the bolide — that is, of the solid body and the portion 

 of compressed air around it." 



15. Conclusion, — The facts at present ascertained, together with 

 the conclusions derived from them, allow us to distinguish four 

 consecutive periods in the existence of meteorites : (I) primor- 

 dial formation; (2) progressive movement through cosmical 

 space; (3) fall to the terrestrial surface ; (4) the fallen substances 

 themselves now become subjects of scientific investigation. They 

 are at once subjects of investigation and meditation for the mine- 

 ralogist,the chemist, the physicist, the meteorologist, the geologist, 

 the geographer, and the astronomer. The English translation 

 of von Haidinger's " Considerations on the Phenomena attend- 

 ing the Fall of Meteorites on the Earth," read before the Im- 

 perial Academy of Vienna, March 14, 1881, was published 



* Report to the Brit. Assoc. 1866, p. 146. 



