68 LIGHT SCIENCE FOR LEISURE HOURS. 



aid will be derived from the various government ob- 

 servatories. 



And now let us inquire why so much interest is at- 

 tached to a phenomenon which appears, at first sight, 

 to be so insignificant. Transits, eclipses, and other 

 phenomena of that nature, are continually occurring, 

 without any particular interest being attached to them. 

 The telescopist may see half a dozen such phenomena 

 in the course of a night or two, by simply watching 

 the satellites of Jupiter, or the passage of our moon 

 over the stars. Even the great eclipse of 1868 did 

 not attract so much interest as the coming transit of 

 Yenus, yet that eclipse had never been equalled in im- 

 portance by any which has occurred in historic times, 

 and hundreds of years must pass before such another 

 happens, whereas transits of Venus are far from being 

 so uncommon. 



The fact is, that Yenus gives us the best means we 

 have of mastering a problem which is one of the most 

 important within the whole range of the science of 

 astronomy. "We use the term important, of course, 

 with reference to the scientific significance and interest 

 of the problem. Practically, it matters little to us 

 whether the sun is a million of miles or a thousand 

 millions of miles from us. The subject must in any 

 case be looked upon as an extra-parochial one. But 

 science does occasionally attach immense interest to 

 extra-parochial subjects. And this is neither unwise 



