A FALLING STAR. 209 



closed shutter is rendered visible, are no doubt mainly of 

 organic origin, but they must also frequently comprise 

 the meteoric granules. These motes gradually subside 

 upon the tops of your bookcases or into other congenial 

 retreats to form that dust of which good housekeepers 

 have such a horror. It is certain that the great majority 

 of the particles of which ordinary dust is constituted have 

 purely terrestrial sources which it would be impossible to 

 endow with any romantic interest. It is equally certain 

 that in a loathed dust-heap are many atoms which, con- 

 sidering their celestial origin and their transcendent 

 voyages, would have merited a more honoured resting- 

 place." 



The discovery of the height at which the streaks of 

 shooting stars are produced is an important element in 

 obtaining any precise knowledge of these bodies. To de- 

 termine it requires the joint action of at least two observers 

 situated at stations widely distant. It will thus be seen 

 that the occasions on which such observations can be 

 obtained are mainly fortuitous. We cannot foretell the 

 occurrence of conspicuous shooting stars so as to enable 

 the two observers to arrange a combined system of obser- 

 vations. We can no doubt in certain cases predict the 

 advent of a shower of shooting stars, but then the very 

 profusion in which the meteors appear tends to baffle any 

 preconcerted agreement, because it is so difficult to insure 

 that identical streaks shall be observed at the two stations. 

 It does, however, sometimes happen that a shooting star 

 observed in one place can by a time comparison be proved 

 to be identical with a shooting star observed in another 

 place. If the two observers have each possessed the skill 



