179 



SCIENTIFIC SIDE-LIGHTS 



Disintegration 

 Distances 



parachute to permit the wind the easier to 

 carry them for some distance before falling, 

 or to drift them on the surface of the snow 

 or i ce> BEAL Seed Dispersal, ch. 5, p. 39. 

 (G. & Co., 1898.) 



873. DISPUTATION ON NAMES 

 RATHER THAN THINGS Agreement amid 

 Controversy. A man that is of judgment 

 and understanding shall sometimes hear ig- 

 norant men differ, and know well within 

 himself that those which so differ mean 

 one thing, and yet they themselves would 

 never agree; and if it come so to pass in 

 that distance of judgment which is between 

 man and man, shall we not think that God 

 above, that knows the heart, doth not dis- 

 cern that frail men, in some of their con- 

 tradictions, intend the same thing; and ac- 

 cepteth of both? BACON Essays, essay 4, 

 Of Revenge, p. 15. (W. L. A.) 



874. DISTANCE OF ONLY ONE STAR 

 CERTAINLY KNOWN Tho no discredit 

 whatever can attach to astronomers for fail- 

 ing to determine exactly quantities which 

 are in reality all but evanescent, yet no more 

 reliance must be placed on the estimates 

 of star-distances than shall appear to be jus- 

 tified by the accordance of different and in- 

 dependent determinations. ... So that 

 the startling but inevitable conclusion is 

 deduced that there is but one star in the 

 heavens of whose distance astronomers have 

 any definite ideas. This star is the one 

 known as Alpha Centauri ; and hitherto all 

 observations agree in placing it at about 

 twenty-two millions of millions of miles 

 from the earth. PROCTOR Our Place among 

 Infinities, p. 167. (L. G. & Co., 1897.) 



875. DISTANCE OF SUN FROM 

 EARTH Expressed in Speed of Cannon-ball 

 and of Railroad Train. As to the distance 

 of ninety-three million miles, a cannon-ball 

 would travel it in about fifteen years. It 

 may help us to remember that at the speed 

 attained by the limited express on our rail- 

 roads a train which had left the sun for the 

 earth when the " Mayflower " sailed from 

 Delftshaven with the Pilgrim Fathers, and 

 which ran at that rate day and night, would 

 in 1887 still be a journey of some years 

 away from its terrestrial station. The fare 

 at the customary rates, it may be remarked, 

 would be rather over two million five hun- 

 dred thousand dollars, so that it is clear 

 that we should need both money and leisure 

 for the journey. LANGLEY New Astronomy, 

 ch. 1, p. 5. (H. M. & Co., 1896.) 



876. DISTANCE PENETRATED 



Spectroscope Measures Orbits and Speed of 

 Stars by Light That Left Them Forty-seven 

 Years Ago. [Dr. Vogel] from his study of 

 the spectra of the variable star Algol, has 

 been able to determine that both the visible 

 star and its dark companion are somewhat 

 larger than our sun, tho of less density; 

 that their centers are 3,230,000 miles apart, 



and that they move in their orbits at rates 

 of 55 and 26 miles per second respectively; 

 and this information, it must be remem- 

 bered, has been gained as to objects the 

 light of which takes about forty-seven years 

 to reach us! WALLACE The Wonderful Cen- 

 tury, ch. 6, p. 48. (D. M. & Co., 1899.) 



877. DISTANCES, INCONCEIVABLE, 

 OF THE STARS Light Millions of Years in 

 Coming Thence Exalted Ideas of Time and 

 Space. Now, light takes more than eight 

 minutes in reaching us from the sun, whose 

 distance is more than 91,000,000 of miles; 

 and it is easily calculated that the long 

 journey from Sirius cannot be traversed in 

 less than fifteen years. More probably it re- 

 quires upwards of twenty years; and the 

 greater number of the stars we see on a dark 

 and clear night lie very much farther away 

 than Sirius. Some of them certainly lie at 

 distances which light can only traverse in 

 hundreds of years. So soon as we turn, 

 however, to telescopic stars, the range of 

 time over which our vision extends is enor- 

 mously increased, and it is certainly not too 

 much to say that some of the fainter stars 

 revealed by the great Rosse telescope lie at 

 distances so enormous that their light has 

 taken more than a hundred thousand years 

 in reaching us. Then beyond these stars lie 

 millions and millions of orbs yet farther 

 away. There is no limit to the range of 

 space occupied thus with the work of God's 

 hands. All that has been taught us by as- 

 tronomy suggests the lesson that every mo- 

 ment light reaches this earth from unseen 

 orbs so far away that the journey over the 

 vast abysses separating us from them has 

 not been completed in less than millions of 

 years. PROCTOR Expanse of Heaven, p. 202. 

 (L. G. & Co., 1897.) 



878. 



Yet Far-off Stars 



Obey Unchanging Law. But it was not 

 merely in the region of the attraction of our 

 sun that the law of gravitation was found to 

 hold. With regard to the fixed stars, it was 

 found that double stars moved about each 

 other in elliptical paths, and that therefore 

 the same law of gravitation must hold for 

 them as for our planetary system. The dis- 

 tance of some of them could be calculated. 

 The nearest of them, a in the constellation of 

 the Centaur, is 270,000 times further from 

 the sun than the earth. Light, which has a 

 velocity of 186,000 miles a second, which 

 traverses the distance from the sun to the 

 earth in eight minutes, would take four 

 years to travel from a Centauri to us. The 

 more delicate methods of modern astronomy 

 have made it possible to determine distances 

 which light would take thirty-five years to 

 traverse as, for instance, the pole-star; 

 but the law of gravitation is seen to hold, 

 ruling the motion of the double stars, at dis- 

 tances in the heavens, which all the means 

 we possess have hitherto utterly failed to 

 measure. HELMHOLTZ Popular Lectures, 

 lect. 4, p. 149. (L. G. & Co., 1898.) 



