'Germs 

 Glaciers 



SCIENTIFIC SIDE-LIGHTS 



282 



divided, as to its length, into ten thousand 

 parts we utterly fail to grasp any notion 

 of the size indicated. An appeal to figura- 

 tive description, while more graphic in char- 

 acter perchance, yet leaves us with the dim- 

 mest conceptions of the dimensions of germs. 

 One writer tells us that on the area of a 

 single square inch we could place, in a 

 single layer, a population of common germs 

 cr bacteria one hundred times as great as 

 the population of London. Graphic as is 

 this estimate, the idea of the actual size 

 of the individual germs remains simply un- 

 attainable. It is this diminutive size com- 

 pared with the great results in the way of 

 disease certain of these germs may and do 

 produce, which is more than sufficient to 

 appal us. WILSON Glimpses of Nature, ch. 

 26, p. 84. (Hum., 1892.) 



1373. GIANTS AMONG THE SUNS 

 Alpha Ccntauri Sirius Equals Two Thou- 

 sand Suns Like Ours in Size. We have 

 seen, however, that Alpha Centauri gives out 

 about three times as much light as our sun. 

 It follows that Sirius shines in reality three 

 hundred times more brightly than the sun. 

 Now, this implies that if the surface of 

 Sirius is of the same intrinsic brightness as 

 the sun's that is, if on the average each 

 square mile of the surface of Sirius gives 

 out the same quantity of light as each square 

 mile of the sun's surface then the surface 

 of Sirius must be 300 times as large as the 

 sun's. It would follow that the diameter of 

 Sirius is between 17 and 18 times as large 

 as the sun's. (For 17 times 17 are less 

 than 300, and 18 times 18 are greater than 

 300.) Hence the volume of Sirius would be 

 about 2,200 times as great as the sun's 

 (this number 2,200 being obtained by multi- 

 plying 300 by 17, which is nearly equiva- 

 lent to multiplying 17^, twice into itself). 

 This is on the supposition of equal surface- 

 luster ; and it cannot be regarded as certain 

 that Sirius is not considerably brighter than 

 our sun as respects his actual surface. Of 

 course if this is the case we cannot assume 

 that Sirius is larger in so great a proportion 

 as when we suppose his intrinsic luster the 

 same as the sun's. 



But it is worthy of notice that the emi- 

 nent French physicist Ste.-Clair-Deville con- 

 siders it impossible that under any circum- 

 stances a surface can be much hotter or 

 more luminous than the solar surface. We 

 shall probably be within the limits of fact 

 if we regard the surface of Sirius as not 

 more than twice as bright as the sun's. 

 This would leave his surface 150 times 

 larger than the sun's, or, for convenience of 

 reckoning, say 144 times; his diameter 

 would thus be twelve times the sun's, and 

 his volume 1,728 times the sun's. 



Have I not rightly called Sirius a " king 

 of suns"? From that glorious orb, nearly 

 2,000 such orbs as the sun, that great and 

 mighty globe, instinct with fire and life, 

 might be formed, each fit to be the center of 

 a scheme of circling worlds as important as 



that over which our sun bears sway! PROC- 

 TOR Expanse of Heaven, pp. 243-245. (L. G. 

 & Co., 1897.) 



1374. GIANTS OF PRIMEVAL DAYS 



The Old Man of Cromagnon. The reader, 

 reflecting on what he has learned from his- 

 tory may be disposed here to ask : " Must 

 we suppose Adam to have been one of these 

 Turanian men, like ' the old man of Cromag- 

 non ' " ? In answer, I would say that there 

 is no good reason to regard the first man as 

 having resembled a Greek Apollo or an 

 Adonis. He was probably of sterner and 

 more muscular mold. But the gigantic 

 paleolithic men of the European caves are 

 more probably representatives of that fear- 

 ful and powerful race who filled the ante- 

 diluvian world with violence, and who re- 

 appear in postdiluvian times as the Anakim 

 and traditional giants, who constitute a fea- 

 ture in the early history of so many coun- 

 tries. Perhaps nothing is more curious in 

 the revelations as to the most ancient cave- 

 men than that they confirm the old belief 

 that there were " giants in those days." 

 DAWSON Facts and Fancies in Modern Sci- 

 ence, lect. 4, p. 169. (A. B. P. S.) 



1375. GIANTS OF THE VEGETABLE 

 KINGDOM Plants and Flowers of the Tropics. 

 In the tropics, plants are more succulent, 

 of a fresher green, and have larger and 

 more glossy leaves, than in the northern re- 

 gions. Social plants, which give such a 

 character of uniformity to European vege- 

 tation, are almost wholly absent in the 

 equatorial zone. Trees, almost twice as high 

 as our oakSj there bloom with flowers as 

 large and splendid as our lilies. On the 

 shady banks of the Magdalena Kiver, in 

 South America, grows a climbing Aristolo- 

 chia, whose blossoms, measuring four feet 

 in circumference, the Indian children sport- 

 ively draw on their heads as caps. In the 

 South Indian Archipelago, the flower of the 

 Rafflesia is nearly three feet in diameter, 

 and weighs above fourteen pounds. HUM- 

 BOLDT Views of Nature, p. 230. ( Bell, 1896. ) 



1376. GIBRALTAR, STRAITS OF 



Current Flowing from Atlantic into Medi- 

 terranean Supply -without Return A 

 Problem in Nature. It is well known that 

 a powerful current sets constantly from the 

 Atlantic into the Mediterranean, and its 

 influence extends along the whole southern 

 borders of that sea, and even to the shores 

 of Asia Minor. Captain Smyth found, dur- 

 ing his survey, that the central current ran 

 constantly at the rate of from three to six 

 miles an hour eastward into the Mediter- 

 ranean, the body of water being three miles 

 and a half wide. But there are also two 

 lateral currents one on the European and 

 one on the African side, each of them about 

 two miles and a half broad, and flowing at 

 about the same rate as the central stream. 

 These lateral currents ebb and flow with the 

 tide, setting alternately into the Mediter- 

 ranean and into the Atlantic. The excess 



