68 



POPXILAR SCIENCE NEWS. 



[May, 1889 



steps of elevation of a mountain region. And that 

 the more particular formation of mountains, giving 

 them their characteristic forms — peaks, ridges, 

 tables, cmgs — proceeded slowly and gradually, is 

 evident in the fact that the sole cause was the erosive 

 or denudating action of flowing water. This same 

 agent (river-erosion) sculptured out the valleys ; 

 and that this process was a gradual one, is manifest 

 in the banks, clifts, or terraces that show the height 

 of the water at former periods. Indeed, one has 

 only to consider carefully the eftects of water in 

 motion, from the time it falls as rain to the time it 

 enters the sea as rivers, to understand that all the 

 features of our old earth's face have been shaped 

 slowly and gradually. Or, adhering to the method 

 of observation, the features themselves show with 

 equal clearness that this has been a characteristic of 

 their history. 



3. The rocks not only record the history of the 

 continents and their features, but indicate strongly 

 that our earth has been evolved from a primordial 

 homogeneous mass. Evidence upon this question 

 is furnished by the igneous and semi-igneous or 

 metamorphic rocks. It need only be said here, that 

 these rocks show unmistakably that they were for- 

 merly in a fused or melted condition, due to the 

 interior heat of the earth, and thus furnish strong 

 evidence in favor of the view that our globe was 

 once in the condition of an incandescent fluid of 

 uniform composition. If this be true, the passage 

 of the earth from this state to that of which we have 

 an authentic record in the stratified rocks, must 

 have been gradual and progressive, — that is, one of 

 evolution, — since it was consequent upon the slow 

 cooling off" of the mass. 



It may, therefore, be considered that the scientific 

 doctrine of evolution, as applied to the earth, is 

 absolutely demonstrated. We may speak of the 

 evolution of the earth, not as a theory, but as a fact. 

 The agents, or causes, of the evolution are the forces 

 of nature — the forces of physics and chemistry. 

 We may think of the primordial earth as a great 

 plastic globe, abandoned to the action of these 

 forces, and by them gradually and progressively 

 molded and fashioned to its present shape. But it 

 is important to guard against the idea that the work 

 of the evolution of the earth has been completed. 

 The process is now going on, just as surely as at 

 any time in the past. The same agents are at work, 

 slowly but inevitably carrying forward our earth in 

 the path of a further evolution. The changes in 

 the face of the earth now taking place about us, are 

 continuous with those that have been going on dur- 

 ing the millions of years of the past. 



The Cosmos. — Looking from our earth to the 

 countless worlds that people space, the question 

 arises, whether here, too, a great law of evolution is 

 in operation. It may be said at once that we do not 

 know what the process has been by which the worlds 

 were made; the cosmos contains within itself no 

 '•ecord of its history that we can interpret with the 

 certainty with which we read that of the rocks of 

 the earth. Nevertheless, there are certain facts 

 which indicate strongly that evolution is a great 

 universal law, penetrating the farthest realms of 

 space, and enduring to the remotest limits of time; 

 that just as gravitation is the great principle by 

 which all the heavenly bodies are sustained in 

 space, so evolution is a great principle by which 

 they have been formed in time. 



We shall best understand the grounds of this idea 

 of world-evolution by calling to mind that, from cer- 

 tain facts in regard to the forms, motions, densities, 

 etc., of the planets, astronomers were long ago led 

 to suspect that our planetary system was formed by 

 a process of evolution. The nebular hypothesis. 



set forth by Laplace in 1799, is purely an hypothesis 

 of the evolution of the planets and their satellites 

 from a primal nebulous mass. Imagine a huge ex- 

 panse of fire-mist, rotating about its centre, and 

 gradually contracting by loss of iieat. Under these 

 conditions, great rings are thrown oft' from the ex- 

 terior, and these finally consolidate into spheres, 

 revolving upon their own axes at the same time 

 that they describe orbits about the original centre — 

 now a flaming sun. In this way, briefly stated, was 

 our solar system formed. It is sufficient to say that 

 this hypothesis has received the careful attention of 

 all astronomers since Laplace's time, and that by 

 many it is considered as having a high degree of 

 probability. As intimated above, it furnishes an 

 explanation of the chief planetary phenomena. If, 

 therefore, evidence points to an evolutionary process 

 as the manner of formation of that portion of the 

 universe best within reach of astronomical study, 

 we have an a priori ground for thinking that the 

 same is true for the entire cosmos. 



This conclusion finds strong support in the recent 

 discovery, made by the use of the spectroscope, that 

 all the heavenly bodies appear to be composed of 

 the same chemical elements. This indicates a com- 

 mon origin for all, and makes the view of a primal 

 universal nebula (fire-mist) something more than a 

 mere speculation. But if this was the original con- 

 dition of the cosmos, it is impossible not to think 

 that it has reached its present constitution by a slow, 

 progressive mutation — that is, by evolution. 



A theory of the cosmos has recently been brought 

 forward by Lockyer, the eminent English astrono- 

 mer, and has received general attention. It sup- 

 poses that the heavenly worlds have been formed by 

 a process of slow aggregation of meteoric bodies. 

 It assumes a primal nebulous condition of the uni- 

 verse, and the nature of the changes by which the 

 present constitution has come to be, is referred to 

 by the author as an evolution. 



Thus we see that we have evidence, amounting to 

 actual demonstration, that the history of the earth 

 has been one of evolution ; and that no theory of the 

 cosmos, accounting for the known facts of astronomy; 

 can be framed that does not recognize the same prin- 

 ciple as dominant in the whole realm of physical 

 nature. 



fOriginal in The Popular Science AeM«.J 

 CORAL. 



Although the coral polyps are so simple and hum- 

 ble, God has given to no other animal the power to 

 add so greatly to the beauty of the surface of the 

 earth, as these silent ocean-workers. Coral is sim- 

 ply the skeleton of the polyps. They take in lime 

 from the sea, and thus secrete a framework or coral. 



There are no muddy shores, no cold currents to 

 strike them, no icy water, where the coral insect 

 flourishes. At the depth of twenty or thirty fath- 

 oms the architecture begins, and ceases when the 

 coral rock reaches the surface of the water. Near 

 the shore of an island, which is but the summit of a 

 mountain in the sea, a fringe of coral is formed. 

 The fringing reef, by its growth and the sinking of 

 the island, becomes a barrier reef. A coral island, 

 or atoll, is the result of a further subsidence of the 

 bottom of the ocean. 



On the reefs of coral the ocean waves deposit sand 

 and sea-weed, and from the seed brought by many 

 agencies to the soil thus formed, a beautiful vegeta- 

 tion springs up. Very beautiful must be these "sea- 

 snatched isles." A low rim of land, mirroring its 

 palm trees in the clear, calm lagoon of water it 

 encloses, with the restless sea forever dashing and 

 breaking against it. When there is "calm on the 

 seas, and silver sleep, and waves that sway them- 

 selves in rest," what a delight it must be to look 



down into the still depths of the ocean, and see the 

 beautiful life that is there — most beautiful, the coral 

 groves of every hue and form. 



The rate at which coral grows is but half a foot a 

 century, yet some of the most important changes 

 which our earth has undergone have been wrought 

 by these animalcuUc. And still the great work goes 

 silently on, and the ocean realms are dotted with 

 emerald gems, and shores are fringed with danger 

 for many a gallant ship freighted with human souls. 



Were it not for the coral polyps, where now there 

 are two hundred islands in the Pacific, there would 

 be less than twenty. So a wise Providence has. 

 made these apparently insignificant insects the 

 agents for some of his most wonderfid works. 



W. 



THE CAMEL'S HUMPS. 



Structurally, of course, the humps are nothfng^ 

 — mere lumps of fat, collected under a convenient fold 

 of the skin, and utterly unprovided for in the frame- 

 work of the skeleton. When the animal is at its 

 best and well fed, they are full and plump, standing 

 up on his back firm and upright ; but on a long 

 journey they are gradually absorbed to keep up the 

 fires that work the heart and legs, and in the cara- 

 van camels which arrive at the coast, the skin hangs 

 over, an empty bag, upon the creature's flanks, bear- 

 ing witness to the scarcity of external food during 

 the long, forced march from the interior. A starved 

 small camel in this state of health, far more closely 

 resembles a Peruvian llama than any one who has 

 only seen the fine, well-kept beasts in European 

 menageries or zoological gardens could readily 

 imagine. 



But water is even scantier in the desert than food ; 

 and against want of water, therefore, the camel has 

 had to provide himself, functionally at least, if not 

 structurally, quite as much as against want of herb- 

 age. His stomach has accordingly acquired the 

 power of acting as an internal reservoir, and he can 

 take in as much water at the Bahrs or Wadys, where 

 he rests for a while on his toilsome march, as will 

 supply his needs for four or five days together. 

 There are some diflerences in this respect, however, 

 between the two chief varieties of the camel. The 

 African kind is most abstemious, and best adapted 

 to sandy deserts; the Bactrian, a product of more 

 varied and better-watered country, is larger and 

 stronger, but less patient of hunger and thirst, 

 while at the same time it can manage to subsist and 

 to make its way into a somewhat rockier and more 

 rugged country. — Gr.'^nt Allen, in the Popular 

 Science Monthly. 



SCIENTIFIC BREVITIES. 



Quicksilver Ore in layers was discovered in the 

 year 1879 at a place called Nikitowka, in Russia. 

 It is a station on the Kursk-Charkow-Asow Rail- 

 way. In 1885 a company was formed for working 

 this ore, and w'ork commenced in the following 

 year. Thus, since April, 1886, or thereabouts, the 

 production of quicksilver has become a new branch 

 of mining industry in that country, which promises 

 to give fairly satisfactory results. 



Development of Seeds. — According to Schu- 

 bater, the majority of plants produce larger and 

 heavier seeds at the north than at the equator, and 

 this, according to him, is due to the long duration 

 of the days of summer, and to the long exposure to 

 the sun. Beans carried from Christiania to Dron- 

 theim have furnished in the latter locality, seeds that 

 had gained sixty per cent, in weight. Thyme from 

 Lyons, planted at Drontheim, has gained seventy- 

 one per cent, in weight. On the contrary, the .seeds 

 of northern plants, developed in more temperate 

 climates, lose in weight. 



