SHOOTING STARS. 267 



in the following words : '* these approximations need no comment, 

 must we regard these falling stars as swarms of small comets or 

 rather as the product of the dissolution of so many great comets ?" 

 Since these deductions of Schiaparelli were first promulgated his 

 theory has received in several instances very satisfactory proofs by 

 other singularly close coincidences that have been found to exist 

 between comets and meteor showers, and as time goes on it 

 becomes more firmly established with each addition to our 

 knowledge. No less than seventy meteor systems are found to 

 have elements agreeing more or less closely with comets, but the 

 agreements are not, it is true, sufficiently exact in many cases to 

 warrant the assumption that they are identical. 



Passing on, now, to refer to other facts we find that these 

 shooting stars exhibit great variety of motion and appearance. If 

 on a clear dark night when there is no moon, we will attentively 

 note their apparent paths amongst the stars, we shall see that 

 while many travel with a slow stately motion, others dart along 

 with quick transient speed ; that while some fall vertically, others 

 stream by in horizontal courses, some directed to the right, some 

 to the left ; others again will have slanting directions, and all will 

 seem to vary as regards the lengths of the visible paths. We 

 shall further see that they appear in every region of the sky, and 

 if their courses are plotted down upon a star chart or globe, it will 

 be found that there are several points at which, if they are carried 

 backwards in the same line of motion, they meet at a focus. 

 These are called the radiant points and give the positions in space 

 from which the meteors are directed. The determination of these 

 radiant points forms an important item in the work of meteor 

 observers because it affords data for the calculation of the orbit. 



The labours of Heis, Greg, Schmidt and others, have enriched 

 this special department with a mass of valuable facts ; their 

 catalogues contain several hundreds of these meteor centres, some 

 of them affording by their accordances with comets, fall and 

 certain indication of the theory which has closely associated them 



