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POPULAR SCIENCE MONTHLY 



ceiving magnets, and messages can Oppolzer, of the planet's variability, 

 thus be transmitted practically simul- A variable planet, with a range of- 



The Telegraphone. 



taneously to any number of stations. 

 It is said also that the magnets may, in 

 this way, be used as a telephonic relay, 

 which would be a result of the utmost 

 practical importance. 



THE PLANET EROS. 

 The little planet Eros bids fair to 

 hold the attention of astronomers for 

 several years to come. Before the ob- 

 servations necessary for the determina- 

 tion of the sun's distance had been com- 

 pleted, came the announcement, by Dr. 



variation, such as Eros has shown, is 

 in itself something new and striking, 

 but this is only the beginning of the 

 problem. Several hundred stars are 

 known to vary their light periodically, 

 and some advance has been made in 

 the theory of their variability. Varia- 

 ble stars, however, do not become in- 

 variable, neither do invariable stars, 

 after a time, become variable. From a 

 variable planet, having an extremely 

 short period and large range of vari- 

 ation, Eros recently became invariable. 



