204 COSMOS. 



Baurait suffire a I'explication des variations signalees par cet 

 astronome" — "that the supposition of intermittent variations 

 in the diaphaneity of the atmosphere would not suffice for the 

 explanation of the changes indicated by that astronomer. ' 



Immediately after the observations of this great astronomer 

 at Paris, and of his friend Fatio de Duillier, an inclination to 

 similar labors showed itself in Indian travelers (Father Noel, 

 De Beze, and Duhalde) ; but isolated reports (for the greater 

 part only describing the gratification experienced at the un- 

 usual prospect) are not available for the sound discussion of 

 the causes of the variabihty. It is not by rapid travels or so- 

 called voyages round the world, as the labors of the active 

 Horner have recently shown (Zach, Monatl. Coi'resp., bd. x., 

 p. 337-340), that tlie deserved object is to be obtained. It 

 is only by a permanent stay of several years in some tropical 

 country that the problem of variable configuration and lu- 

 minous intensity can be solved. Therefore, the most is to be 

 expected for the subject which now occupies us, as well as for 

 the entire science of meteorology, from the ultimate difilision 

 of scientific culture throughout the equinoctial world — the for- 

 mer Spanish America — where large populous towns, Cuzco, 

 La Paz, Potosi, are situated between 10,700 and 12,500 feet 

 above the level of the sea. The numerical results which 

 Houzeau was able to obtain, though certainly based upon 

 only a small number of observations, make it probable that 

 the major axis of the zodiacal light no more coincides with 

 the plane of the Sun's equator, than the vapory mass of the 

 ring whose molecular condition is unknown to us extends be- 

 yond the Earth's orbit. (Schum., Astr. Nachr., No. 492.) 



V. 



FALLING STARS, FIRE-BALLS, AND METEORIC STONES. 



Since the spring of 1845, when I published the Delinea- 

 tions of Nature, or the general survey of cosmical phenomena, 

 the pri3vious results of the observation of aerolites and periodic 

 streams of falling stars have been abundantly extended and 

 corrected. Much has been subjected to a stricter and more 

 careful criticism, especially the discussion, so important for 

 the whole of this mysterious phenomenon, of the divergence, 

 i. €., the situation of the point of departure .in the recurring 

 epochs of swarms of falling stars. The number of these 

 epochs, also, of which, for a bng time, the August and No- 



