Carth 

 Zanh's 



SCIENTIFIC SIDE-LIGHTS 



190 



is as follows : " As time never fails, and the 

 universe is eternal, neither the Tanais nor 

 the Nile can have flowed forever. The 

 places where they rise were once dry, and 

 there is a limit to their operations; but 

 there is none to time. So also of all other 

 rivers; they spring up, and they perish; 

 and the sea also continually deserts some 

 lands and invades others. The same tracts, 

 therefore, of the earth are not some always 

 sea, and others always continents, but every- 

 thing changes in the course of time." 

 LYELL Principles of Geology, bk. i, ch. 2, p. 

 13. (A., 1854.) 



932. EARTH, ELEVATION AND SUB- 

 SIDENCE OF Slow Movement through Cen- 

 turies. Lyell estimated that the average 

 rate of rise in Scandinavia has been about 

 two and a half feet per century. At the 

 North Cape the rise may have been as much 

 as five or six feet per century. Observa- 

 tions made at the temple of Jupiter Sera- 

 pis, between October, 1822, and July, 1838, 

 showed that the ground was sinking at the 

 rate of about one inch in four years. Since 

 the Roman period, when this temple was 

 built, the ground has sunk twenty feet be- 

 low the waves. Now the floor of the temple 

 is on the level of the sea. Lyell remarks 

 that if we reflect on the dates of the prin- 

 cipal oscillations at this place there appears 

 to be connection between the movements of 

 upheaval and a local development of vol- 

 canic heat, whilst periods of depression are 

 concurrent with periods of volcanic quies- 

 cence. MILNE Earthquakes, ch. 21, p. 351. 

 (A., 1899.) 



933. EARTH ENRICHED BY MATE- 

 RIALS FROM AFAR Matter from Distant 

 Space Continually Drawn In. Let it suffice 

 that we recognize, as one of the earliest 

 stages of our earth's history, her condition 

 as a rotating mass of glowing vapor, cap- 

 turing then as now, but far more actively 

 then than now, masses of matter which ap- 

 proached near enough, and growing by these 

 continual indrafts from without. From 

 the very beginning, as it would seem, the 

 earth grew in this way. This firm earth on 

 which we live represents an aggregation of 

 matter not from one portion of space, but 

 from all space. All this is upon and within 

 the earth, all vegetable forms and all ani- 

 mal forms, our bodies, our brains, are 

 formed of materials which have been drawn 

 in from those depths of space surrounding 

 us on all sides. This hand that I am now 

 raising contains particles which have trav- 

 eled hither from regions far away amid the 

 northern and southern constellations, par- 

 ticles drawn in towards the earth by proc- 

 esses continuing millions of millions of ages, 

 until after multitudinous changes the chap- 

 ter of accidents has so combined them, and 

 so disturbed them in plants and animals, 

 that after coming to form portions of my 

 food they are here present before you. Pass- 

 ing from the mere illustration of the 



thought, is not the thought itself striking 

 and suggestive, that not only the earth on 

 which we move, but everything we see or 

 touch, and every particle in body and brain, 

 has sped during countless ages through the 

 immensity of space? PROCTOR Our Place 

 among Infinities, p. 9. (L. G. & Co., 1897.) 



934. EARTH FEELS CHANGES ON 



SUN Cosmic Influence Auroras Follow Vari- 

 ation of Sun-spots. The relation between 

 the aurora borealis and the sun-spots was 

 studied and finally proved by Fritz, Loomis, 

 and Levering. Fritz appears to have been 

 the first who distinctly laid down the law 

 that the number and importance of the 

 auroras follow exactly the same variation 

 as the spots on the sun, so that the epochs 

 of the maxima and minima coincide almost 

 exactly for the two orders of phenomena. 

 ANGOT Aurora Borealis, ch. 5, p. 96. (A.. 

 1897.) 



935. EARTH FORMING STILL 



Ceaseless Circulation of the Solid Materials 

 of the Globe. Over every part of the earth's 

 surface these three grand operations of the 

 disintegration of old rock-masses, the trans- 

 port of the materials so produced to lower 

 levels, and the accumulation of these ma- 

 terials to form new rocks, are continually 

 going on. It is by the varied action of these 

 denuding agents upon rocks of unequal 

 hardness, occupying different positions in 

 relation to one another, that all the external 

 features of hills, and plains, and mountains 

 owe their origin. JUDD Volcanoes, ch. 10, p. 

 284. (A., 1899.) 



936. EARTH HELD TO BE A GREAT 

 METEORITE But in recent years a num- 

 ber of very important facts have been dis- 

 covered which may well lead us to devote a 

 closer attention to the composition and 

 structure of meteorites. It has been shown, 

 on the one hand, that some meteorites con- 

 tain substances precisely similar to those 

 which are sometimes brought from the 

 earth's interior during volcanic outbursts; 

 and, on the other hand, there have been de- 

 tected, among some of the ejections of vol- 

 canoes, bodies which so closely resemble 

 meteorites that they were long mistaken for 

 them. Both kinds of observation seem to 

 point to the conclusion that the earth's in- 

 terior is composed of similar materials to 

 those which we find in the small planets 

 called meteorites. JUDD Volcanoes, ch. 11, 

 p. 315. (A., 1899.) 



937. EARTH, HUMAN DWELLINGS 

 ENGULFED IN Fissures Opened and Closed 

 in Earthquake. Almost all large earth- 

 quakes have produced cracks in the ground. 

 The cracks which were found in the ground 

 at Yokohama (February 22, 1880) were 

 about two or three inches wide, and from 

 twenty to forty yards in length. They could 

 be best seen as lines along a road running 

 near the upper edge of some cliffs which 

 overlook the sea at that place. The reason 



