PHYSICS OF THE GLOBE. 209 



zontal dimensions. These clouds play the part of humid con- 

 ductors, connecting inferior with superior strata ; and their 

 dissolution, in the form of rain, is connected with electric 



phenomena. 



Meteors and Zodiacal Light. 



Although meteors are to be considered as proper subjects 

 of study for the astronomer, yet often, by their entry into the 

 earth's atmosphere, they come to have a special interest for 

 the meteorologist. The phenomena shown by their trains 

 have not yet, that we are aware of, been subjected to any 

 comprehensive study during the past few years; but the im- 

 portant question as to the amount of heat introduced into 

 our atmosphere by the destruction of a part or all of the vis 

 viva of all the meteors that enter therein has been taken up 

 by Govi, who finds that modern discoveries serve to abun- 

 dantly elucidate the subject. It is not, however, likely that 

 the temperature of the lower layers of the air is sensibly af- 

 fected by this source of heat. 



Dr. G. von Niessl communicates to the Astr. JVcich. the re- 

 sults of a preliminary investigation into the Daily Variation 

 of the Shooting-stars, in which he shows that numerous con- 

 clusions deduced from a careful consideration of the theory 

 of the nature and movements of these bodies do not a<n-ee 

 sufficiently well with the observations of the past few years; 

 and he suggests that the true explanation lies in the follow- 

 ing assumptions: first, that the density of the perihelia of 

 the meteoric orbits diminishes with increasing perihelion 

 distance; second, that the orbits are much more frequently 

 hyperbolic than parabolic. 



Some instructions for the observation of Zodiacal Light 

 are given by Serpieri, in the " Meteorologia Italiana " for 1878, 

 in which he calls special attention to the points observed by 

 the Rev. George Jones, and also by Heis and Schiaparelli. 

 Some connection between the zodiacal light and the aurora 

 seems also to be indicated by the observations of Bruno at 

 Mondovi, February 4, 1872. 



In Vol. XXV. of the "Memoires Couronnes" of the Royal 

 Belgian Academy, Houzeau gives a Summary of Astronom- 

 ical and Meteorological Observations made by him in the 

 tropics and adjoining portions of the temperate zone. His 

 observations included the zodiacal light, which was seen on 



