Motion 



SCIENTIFIC SIDE-LIGHTS 



460 



diurnal revolution, we shall find that pas- 

 ,sage to occur some four minutes earlier 

 every evening than it did the evening be- 

 fore. The starry sphere therefore revolves, 

 not in 24 hours, but in 23 hours 56 minutes. 

 In consequence, if we note its position at 

 the same hour night after night, we shall 

 find it to be farther and farther to the west. 

 Let us take, for example, the brightest star 

 in the constellation Leo, . . . and com- 

 monly known as Regulus. If we watch it on 

 the 22d of March, we shall find that it 

 passes the meridian at ten o'clock in the 

 evening. On April 22d it passes at eight 

 o'clock, and at ten it is two hours west of 

 the meridian. On the same day of May it 

 passes at six, before sunset, so that it can- 

 not be seen on the meridian at all. When it 

 first becomes visible in the evening twilight, 

 it will be an hour or more west of the 

 meridian. In June it will be three hours 

 west, and by the end of July it will set dur- 

 ing twilight, and will soon be entirely lost 

 in the rays of the sun. This shows that dur- 

 ing the months in question the sun has been 

 approaching the star from the west, and in 

 August has got so near it that it is no 

 longer visible. Carrying forward our com- 

 putation, we find that on August 21st the 

 star crosses the meridian at noon, and there- 

 fore at nearly the same time with the sun. 

 In September it crosses at ten in the morn- 

 ing, while the sun is on the eastern side. 

 The sun has therefore passed from the west 

 to the east of the star, and the latter can be 

 seen rising in the morning twilight before 

 the sun. It constantly rises earlier and 

 earlier, and therefore farther from the sun, 

 until February, when it rises at sunset and 

 sets at sunrise, and is therefore directly op- 

 posite the sun. In March the star would 

 cross the meridian at ten o'clock once more, 

 showing that in the course of a year the sun 

 and star had resumed their first position. 

 But, while the sun has risen and set 365 

 times, the star has risen and set 366 times, 

 the sun having lost an entire revolution by 

 the slow backward motion we have de- 

 scribed. . . . The path which the sun 

 describes among the stars in his annual 

 revolution is called the ecliptic. ... A 

 belt of the heavens, extending a few degrees 

 en each side of the ecliptic, is called the 

 zodiac. NEWCOMB Popular Astronomy, ch. 

 1, p. 14. (H., 1899.) 



2255. MOTION AS ESSENTIAL IN 

 THE SIDEREAL WORLD AS IN THE OR- 

 GANIC- If, . . . , we imagine the acute- 

 ness of our senses preternaturally height- 

 ened to the extreme limits of telescopic 

 vision, bringing together events separated 

 by wide intervals of time, the apparent re- 

 pose which reigns in space will suddenly 

 vanish. Countless stars will be seen moving 

 in groups in various directions ; nebulae wan- 

 dering, condensing, and dissolving like cos- 

 mical clouds; the Milky Way breaking up 

 in parts and its veil rent asunder. In every 



point of the celestial vault we should recog- 

 nize the dominion of progressive movement 

 just as on the surface of the earth, where 

 vegetation is constantly putting forth leaves 

 and buds and unfolding into blossoms. The 

 celebrated Spanish botanist, Cavanilles, first 

 conceived the possibility of seeing grass 

 grow by placing the horizontal micrometer 

 wire of a telescope with a high magnifying 

 power at one time on the point of a bamboo 

 shoot, at another on the rapidly unfolding 

 flowering stem of an American aloe, precise- 

 ly as the astronomer places the cross of 

 wires on a culminating star. Throughout 

 the whole life of physical nature in the or- 

 ganic, as in the sidereal world, existence, 

 preservation, production, and development, 

 are alike associated with motion as their 

 essential condition. HUMBOLDT Cosmos, vol. 

 i, p. 139. (Translated for Scientific Side- 

 Lights.J 



2256. MOTION, ATOMIC, NOT CON- 

 VERTIBLE INTO CONSCIOUSNESS In his 



celebrated " Address to the Congress of Ger- 

 man Naturforscher," delivered at Leipsic 

 [in 1872] Du Bois-Reymond speaks thus: 

 " What conceivable connection subsists be- 

 tween definite movements of definite atoms 

 in my brain, on the one hand, and on the 

 other hand such primordial, indefinable, un- 

 deniable facts as these: I feel pain or pleas- 

 ure; I experience a sweet taste, or smell a 

 rose, or hear an organ, or see something red. 

 It is absolutely and forever inconceivable that 

 a number of carbon, hydrogen, nitrogen, and 

 oxygen atoms should be otherwise than in- 

 different as to their own position and mo- 

 tion, past, present, or future. It is utterly 

 inconceivable how consciousness should re- 

 sult from their joint action." TYNDALL 

 Fragments of Science, vol. ii, ch. 11, p. 226. 

 (A., 1900.) 



2257. MOTION, CEASELESS, OF LU- 

 MINIFEROUS ETHER We on the earth's 

 surface live night and day in the midst of 

 ethereal commotion. The medium is never 

 still. The cloud canopy above us may be 

 thick enough to shut out the light of the 

 stars, but this canopy is itself a warm 

 body, which radiates its thermal motion 

 through the ether. The earth also is warm, 

 and sends its heat-pulses incessantly forth. 

 It is the waste of its molecular motion 

 in space that chills the earth upon a clear 

 night; it is the return of thermal motion 

 from the clouds which prevents the earth's 

 temperature on a cloudy night from falling 

 so low. To the conception of space being 

 filled we must, therefore, add the conception 

 of its being in a state of incessant tremor. 

 TYNDALL Fragments of Science, vol. i, ch. 

 1, p. 8. (A., 1897.) 



2258. MOTION CONVERTED INTO 



HEAT Iron Made Hot by Hammering. Rob- 

 ert Boyle appears to have seen as clearly 

 as we do to-day that when heat is generated 

 by mechanical means, new heat is called into 

 existence. In describing one of his experi- 



