laments 



fiSS 



SCIENTIFIC SIDE-LIGHTS 



204 



with those of Sirius; these are sodium, 

 magnesium, hydrogen, and probably iron. 

 The lines of hydrogen are abnormally strong 

 compared to those which exist in the solar 

 spectrum. FLAMMARION Popular Astron- 

 omy, bk. vi, ch. 6, p. 609. (A.) 



995. ELEMENTS OF EARTHLY SUB- 

 STANCE FOUND WIDELY DIFFUSED IN 

 SPACE Stitt Surrounded by the Unknown. 

 We cannot, indeed, say that we have ex- 

 plained all spectra; many fixed stars ex- 

 hibit peculiarly banded spectra, probably 

 belonging to gases whose molecules have not 

 been completely resolved into their atoms by 

 the high temperature. In the spectrum 

 of the sun, also, are many lines which we 

 cannot identify with those of terrestrial ele- 

 ments. It is possible that they may be due 

 to substances unknown to us ; it is also pos- 

 sible that they are produced by the excess- 

 ively high temperature of the sun, far 

 transcending anything we can produce. But 

 this is certain, that the known terrestrial 

 substances are widely diffused in space. 

 HELMIIOLTZ Popular Lectures, lect. 4, p. 

 156. (L. G. & Co., 1898.) 



996. ELEMENTS OF TERROR AC- 

 CUMULATED lightnings Attend Volcanic 

 Eruption. Another striking phenomenon 

 which was exhibited in the great eruption 

 of Vesuvius in 1872 was the vivid display of 

 lightning accompanied by thunder. The up- 

 rushing current of steam and rock-frag- 

 ments forms a vertical column, but as the 

 steam condenses it spreads out into a great 

 horizontal cloud which is seen to be made up 

 of the great globes of vapor emitted at suc- 

 cessive explosions. When there is little or 

 no wind the vertical column with a hori- 

 zontal cloud above it bears a striking resem- 

 blance to the stone-pine trees which form so 

 conspicuous a feature in every Neapolitan 

 landscape. Around this column of vapor 

 the most vivid lightning constantly plays 

 and adds not a little to the grand and awful 

 character of the spectacle of a volcanic erup- 

 tion, especially when it is viewed by night. 

 JUDD Volcanoes, ch. 2, p. 28. (A., 1899.) 



997. ELEVATION OF BED OF NILE 



Fertility Encroaching upon the Desert. 

 The bed of the Nile always keeps pace with 

 the general elevation of the soil, and the 

 banks of this river, like those of the Mis- 

 sissippi and its tributaries, are much higher 

 than the flat land at a distance, so that they 

 are seldom covered during the highest inun- 

 dations. In consequence of the gradual rise 

 of the river's bed, the annual flood is con- 

 stantly spreading over a wider area, and 

 the alluvial soil encroaches on the desert, 

 covering, to the depth of six or seven feet, 

 the base of statues and temples which the 

 waters never reached 3,000 years ago. Altho 

 the sands of the Libyan Desert have in some 

 places been drifted into the valley of the 

 Nile, yet these aggressions, says Wilkinson, 

 are far more than counterbalanced by the 

 fertilizing effect of the water which now 



reaches farther inland towards the desert, so 

 that the number of square miles of arable 

 soil is greater at present than at any pre- 

 vious period. LYELL Principles of -Geology, 

 bk. ii, ch. 17, p. 262. (A., 1854.) 



998. ELEVATION, SLOW, OF 

 EARTH'S CRUST Streams Cut Down as. 

 Fast as Surface Is Lifted. Yet, strange to 

 say, none of these earth-movements suc- 

 ceeded in deflecting the main drainage of the 

 [Grand Canon] district. The Colorado and 

 its chief affluents continued to flow in the 

 courses they had attained at the final dis- 

 appearance of the great lake. It is clear, 

 therefore, that the bending and dislocation 

 of the strata must have proceeded very 

 slowly, for the rivers were able to cut their' 

 way across both flexures and faults as fast 

 as these showed at the surface. GEIKIE 

 Earth Sculpture, ch. 3, p. 57. (G. P. P., 

 1898.) 



999. EMBLEM OF DIVINE FULNESS 

 Power of the Sun's Heat Lavish Benefi- 

 cence. Working out the results of the 

 Mount Whitney expedition, he [Langley] 

 was led to conclude atmospheric absorption 

 to be fully twice as effective as had hitherto 

 been supposed. Scarcely sixty per cent., in 

 fact, of those solar radiations which strike 

 perpendicularly through a seemingly trans- 

 lucent sky attain the sea-level. The rest are 

 reflected, dispersed, or absorbed. This discov- 

 ery involved a large addition to the original 

 supply so mercilessly cut down in trans- 

 mission. . . . The sun's heat reaching 

 the outskirts of our atmosphere is capable 

 of doing without cessation the work of an 

 engine of three horse-power for each square 

 yard of the earth's surface. Thus, modern 

 inquiries, tho they give no signs of agree- 

 ment, within any tolerable limits of error, 

 as to the probable temperature of the sun, 

 tend, with growing certainty, to render 

 more and more evident the vastness of the 

 thermal stores contained in the great central 

 reservoir of our system. CLERKE History of 

 Astronomy, pt. ii, ch. 5, p. 279. (Bl., 1893.) 



1000. EMBRYO SHAPED BY VIEW- 

 LESS ARTIST The student of Nature 

 wonders the more and is astonished the less, 

 the more conversant he becomes with her 

 operations ; but of all the perennial miracles 

 she offers to his inspection, perhaps the most 

 worthy of admiration is the development of 

 a plant or of an animal from its embryo. 

 Examine the recently laid egg of some com- 

 mon animal, such as a salamander or a 

 newt. It is a minute spheroid in which the 

 best microscope will reveal nothing but a 

 structureless sac, enclosing a glairy fluid, 

 holding granules in suspension. But strange 

 possibilities lie dormant in that semi-fluid 

 globule. Let a moderate supply of warmth 

 reach its watery cradle, and the plastic mat- 

 ter undergoes changes so rapid and yet so 

 steady and purpose-like in their succession, 

 that one can only compare them to those 

 operated by a skilled modeler upon a form- 



