THE AUGUST AND NOVEMBER METEORS. 393 



its course round the sun, like the planets, in a certain fixed period of 

 years. From this it is evident that the orbits of comets may occur at 

 every possible angle to that of the earth, and that their motion will be 

 sometimes progressive and sometimes retrograde. 



The history of the cosmical cloud does not, however, end with its 

 transformation into a comet. Schiaparelli shows in a striking manner 

 that, as a comet is not a solid mass, but consists of particles, each pos- 

 sessing an independent motion, the head or nucleus nearer the sun 

 must necessarily complete its orbit in less time than the more distant 

 portions of the tail. The tail will therefore lag behind the nucleus in 



Fig. 3. 



Orbit of the November Meteor-Shower. 



the course of the comet's revolution, and the comet, being more and 

 more elongated, will at last be either partially or entirely resolved into 

 a ring of meteors. In this way the whole path of the comet becomes 

 strewed with portions of its mass, with those small, dark meteoric 

 bodies which, when penetrating the earth's atmosphere, become lumi- 

 nous, and appear as falling stars. Instead of the comet, there now re- 

 volves round the sun a broad ring of meteoric stones, which occasion 

 the phenomena we every year observe as the August meteors. 

 "Whether this ring be continuous, and the meteoric masses strewed 

 along the whole course of the path of the original comet, or whether 

 the individual meteors, as in the November shower, have not filled up 

 entirely the whole orbit, but are still partially in the form of a comet, 



