﻿262 Chevalier W. von Haidinger on the Luminous, Thermal, 



but, indeed, applied to cosmical bodies, the conception of magni- 

 tude will always be relative. He concludes, further, from the 

 more intense emission of light in higher atmospherical strata, that 

 such meteors have a greater amount of velocity than those appear- 

 ing with less splendour in the lower regions of the atmosphere. 

 Director Julius Schmidt came to the same conclusion from his 

 observations of the meteors in the course of 1851*. These 

 observations induced Haidinger t to suppose a connexion between 

 the accelerated formation of the luminous envelope in the pro- 

 gress of motion and the tenuity of particles of agglomerations 

 of cosmical pulverulent substance, in conformity with the views 

 expressed in Mr. A. S. HerschePs letter on the nature of pla- 

 netary corpuscles, addressed to Abbe MoignoJ. Dr. E.Weiss has 

 still some doubts about the explanations of the prevalence of fall- 

 ing stars or of meteors, according as the meteoric bodies and the 

 terrestrial globe are moving in the same or in opposite directions. 

 13. Messrs. R. P. Greg and A. S. Herschel published in 1867 

 an ' Atlas of Charts of the Meteor-tracks contained in the Bri- 

 tish-AssociationCatalogue of Observations of Luminous Meteors, 

 extending over the years 1845 to 1866/ This Atlas compre- 

 hends twenty- two celestial charts of Bede (three for January, 

 August, and September, two for February, April, October, and 

 November, and one for each of the five other months), on which 

 are entered the dates of the phenomena, the limits of their 

 duration, the position of the points of radiation, their denomi- 

 nation as proposed by MM. Heis and Greg, and their peculiar 

 characters with regard to all general and special meteoric cur- 

 rents hitherto observed in the northern hemisphere. An appen- 

 dix contains a synoptic Table of the points of radiation in the 

 northern hemisphere from January 1 to June 30, and from 

 July 1 to December 31, and another, for each day of the year, 

 of the radiations of fifty-one epochs of meteoric currents, as de- 

 termined by Professor Heis. A paper published in the f Scien- 

 tific Review/ London, June 1, 1868, has added twelve new points 

 of radiation of meteoric currents to the sixty points already 

 known. Mr. Greg has undertaken the laborious task of redu- 

 cing above one thousand new observations made by M. Jezioli at 

 Bergamo. An enormous amount of observations is also trea- 

 sured and systematically arranged in Messrs. J. Glaisher, R. P. 

 Greg, E. W. Brayley, and A. S. HerschePs " Reports of Observa- 

 tions of Luminous Meteors," addressed to the British Association 

 for the Advancement of Science§. Mr. A. HerschePs spectrum- 



* See Vienna Acad. Proc. vol. xxxvii. pp. 803-820. 

 t Vienna Acad. Proc. vol. xlix. sect. 2, pp. 6-61, January 8, 1864. 

 X See Les Mondes, l e annee, torn. ii. liv. 14, November 5, 1863. 

 § See Report of Brit. Assoc. 1866 & 1867. 



