ABOUT THE STARS 225 



namely, at the rate of nineteen miles a second ! That, I 

 think, is a fact likely to make the sentimental young 

 astronomer as miserable as any of the records of im- 

 mensity. In fact, the only comfort to be got in view of 

 this fact is in the enormous distances which separate us 

 from other stars, and the length of time which must 

 elapse before any serious consequence can ensue from 

 this alarming career. And there is further the prob- 

 ability that the general result of attractions and repulsions 

 in the vast roadway of space will, when the time comes, 

 take us safely past Vega, just as a motor-car passes safely 

 through the traffic and obstructing " refuges " and lamp- 

 standards of the London streets as you recline in it, 

 abandoned to the natural forces described as " chauffeurs." 

 The spectroscope has done no less than photography 

 to reanimate the study of astronomy. The fact is that, 

 with these two helping means of observation, it has 

 become possible for the ordinary man to witness and 

 appreciate some of the discoveries of astronomers, though 

 the true and accurate handling of all that is revealed 

 concerning the stars is essentially a matter of measure- 

 ment, and therefore only to be dealt with strictly by 

 mathematicians. The desire to obtain ever more and 

 more accurate measurement of the movement and the size 

 of the heavenly bodies is the mainspring of all astro- 

 nomical discovery, and, indeed, the attempt to gain more 

 and more detailed measurement of the factors at work 

 is the motive more or less immediate of all accurate 

 investigation of nature. Recently the astronomers of 

 the Royal Observatory at Greenwich have photographed 

 the new comet (the third of 1907) in a way in which no 

 comet has ever been photographed before. On many 

 consecutive nights for several weeks they were at work 

 photographing it on the dry plate, at intervals of two or 

 three hours, and the pictures obtained (which I have 

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