Uniformity 

 Union 



SCIENTIFIC SIDE-LIGHTS 



710 



peated, only be alike in all its circumstances, 

 the result which cometh forth is as rigidly 

 alike, without deficiency, and without devi- 

 ation. . . . But there is a God who liveth 

 and sitteth there, and these unvarying re- 

 sponses of Nature are all prompted by him- 

 self, and are but the utterances of his im- 

 mutability. They are the replies of a God 

 who never changes, and who hath adapted 

 the whole materialism of creation to the 

 demonstration of it. The certainties of Na- 

 ture and of science are, in fact, the vocables 

 by which God announces his truth to the 

 world; and when told how impossible it is 

 that Nature can fluctuate, we are only told 

 how impossible it is that the God of Nature 

 can deceive us. CHALMERS Astronomical 

 Discourses, suppl. disc. 1, p. 213. (R.Ct.,1848.) 



3514. Interruption of 



Eclipse of the Sun Perplexity of Animals. 

 The effect of the waning light on animals 

 [during an eclipse of the sun at Rio de 

 Janeiro, 1865] was very striking. The Bay 

 of Rio is daily frequented by large numbers 

 of frigate-birds and gannets, which at night 

 fly to the outer islands to roost, while the 

 carrion-crows (urubus) swarming in the sub- 

 urbs, and especially about the slaughter- 

 houses of the city, retire to the mountains 

 in the neighborhood of Tijuca, their line 

 of travel passing over San Christovao. As 

 soon as the light began to diminish, these 

 birds became uneasy; evidently conscious 

 that their day was strangely encroached 

 upon, they were uncertain for a moment how 

 to act. Presently, however, as the darkness 

 increased, they started for their usual night 

 quarters, the water-birds flying southward, 

 the vultures in a northwesterly direction, 

 and they had all left their feeding-grounds 

 before the moment of greatest obscurity ar- 

 rived. They seemed to fly in all haste, but 

 were not half-way to 'their night home when 

 the light began to return with rapidly in- 

 creasing brightness. Their confusion was 

 now at its height. Some continued their 

 flight towards the mountains or the harbor, 

 others hurried back to the city, while others 

 whirled about wholly uncertain what to do 

 next. The reestablishment of the full light 

 of noon seemed to decide them, however, 

 upon making another day of it, and the 

 whole crowd once more moved steadily to- 

 ward the city. AGASSIZ Journey in Brazil, 

 ch. 2, p. 52. (H. M. & Co., 1896.) 



3515. Maintained amid 



Contending Forces. Battle within battle 

 must be continually recurring with varying 

 success; and yet in the long run the forces 

 are so nicely balanced that the face of Na- 

 ture remains for long periods of time uni- 

 form, tho assuredly the merest trifle would 

 give the victory to one organic being over 

 another. DARWIN Origin of Species, ch. 1, 

 p. 67. (Burt.) 



3516. Natural Laws Un- 

 changed through All Ages Limitations of 

 the Doctrine. The geological record informs 



us that the general laws of Nature have 

 continued unchanged from the earliest peri- 

 ods to which it relates until the present 

 day. This is the true " uniformitarianism " 

 of geology which holds to the dominion of 

 existing causes from the first. But it does 

 not refuse to admit variations in the in- 

 tensity of these causes from time to time, 

 and cycles of activity and repose, like those 

 that we see on a small scale in the seasons, 

 the occurrence of storms, or the paroxysms 

 of volcanoes. DAWSON Facts and Fancies 

 in Modern Science, lect. 3, p. 119. (A. B. 

 P. S.) 



3517. Slow Recognition 



of the Truth. Woodward did not hesitate, 

 in 1695, to teach that the entire mass of fos- 

 siliferous strata contained in the earth's 

 crust had been deposited in a few months; 

 and, consequently, as their mechanical and 

 derivative origin was already admitted, 

 the reduction of rocky masses into mud, 

 sand, and pebbles, the transportation of the 

 same to a distance, and their accumulation 

 elsewhere in regular strata, were all assumed 

 to have taken place with a rapidity un- 

 paralleled in modern times. This doctrine 

 was modified by degrees, in proportion as 

 different classes of organic remains, such as 

 shells, corals, and fossil plants, had been 

 studied with attention. Analogy led every 

 naturalist to assume that each full-grown 

 individual of the animal or vegetable king- 

 dom had required a certain number of 

 months or years for the attainment of ma- 

 turity, and the perpetuation of its species 

 by generation; and thus the first approach 

 was made to the conception of a common 

 standard of time, without which there are 

 no means whatever of measuring the com- 

 parative rate at which any succession of 

 events has taken place at two distinct peri- 

 ods. This standard consisted of the aver- 

 age duration of the lives of individuals of 

 the same genera or families in the animal 

 and vegetable kingdoms; and the multitude 

 of fossils dispersed through successive strata 

 implied the continuance of the same species 

 for many generations. At length the idea 

 that species themselves had had a limited 

 duration arose out of the observed fact that 

 sets of strata of different ages contained 

 fossils of distinct species. Finally, the opin- 

 ion became general that in the course of ages 

 one assemblage of animals and plants had 

 disappeared after another again and again, 

 and new tribes had started into life to re- 

 place them. LYELL Principles of Geology, 

 bk. i, ch. 10, p. 153. (A., 1854.) 



3518. UNION, CHEMICAL, VS. ME- 

 CHANICALA Mixture Differs from a Com- 

 pound. We cannot say that water consists 

 of hydrogen and oxygen in the same sense 

 that bread consists of flour, or sirup of su- 

 gar, and mortar of lime. We must be very 

 careful not to transfer our ideas of com- 

 position, drawn chiefly from the mixtures 

 we use in common life, directly to chemis- 



