725 



SCIENTIFIC SIDE-LIGHTS 



Utility 

 Value 



leaves no single point of the complex situ- 

 ation accented and standing out for him 

 to begin to act upon. But the sailor, the 

 fireman, and the general know directly at 

 what corner to take up the business. They 

 " see into the situation " that is, they ana- 

 lyze it with their first glance. It is full 

 of delicately differenced ingredients which 

 their education has little by little brought 

 to their consciousness, but of which the nov- 

 ice gains no clear idea. JAMES Psychology, 

 vol. ii, ch. 22, p. 343. (H. H. & Co., 1899.) 



3592. VALE OF FIREFLIES Air 



Laden with Phosphorescent Odor. Riding 

 on the pampas one dark evening an hour 

 after sunset, and passing from high ground 

 overgrown with giant thistles to a low plain 

 covered with long grass, bordering a stream 

 of water, I found it all ablaze with myriads 

 of fireflies. I noticed that all the insects 

 gave out an exceptionally large, brilliant 

 light, which shone almost steadily. The 

 long grass was thickly studded with them, 

 while they literally swarmed in the air, all 

 moving up the valley with a singularly slow 

 and languid flight. When I galloped down 

 into this river of phosphorescent fire my 

 horse plunged and snorted with alarm. I 

 succeeded at length in quieting him, and 

 then rode slowly through, compelled to keep 

 my mouth and eyes closed, so thickly did 

 the insects rain on to my face. The air was 

 laden with the sickening phosphorous smell 

 they emit; but when I had once got free of 

 the broad fiery zone, stretching away on 

 either hand for miles along the moist valley, 

 I stood still and gazed back for some time 

 on a scene the most wonderful and enchant- 

 ing I have ever witnessed. HUDSON Nat- 

 uralist in La Plata, ch. 13, p. 173. (C. & H., 

 1895.) 



3593. VALLEY LIFELESS AND SI- 

 LENT Scenery of the Val del Bove, Mount 

 Etna. This plain has been deluged by re- 

 peated streams of lava; and altho it appears 

 almost level when viewed from a distance, 

 it is in fact more uneven than the surface 

 of the most tempestuous sea. . . . 



An unusual silence prevails; for there are 

 no torrents dashing from the rocks nor any 

 movement of running water in this valley, 

 such as may almost invariably be heard in 

 mountainous regions. Every drop of water 

 that falls from the heavens, or flows from 

 the melting ice and snow, is instantly ab- 

 sorbed by the porous lava ; and such is the 

 dearth of springs that the herdsman is com- 

 pelled to supply his flocks, during the hot 

 season, from stores of snow laid up in hol- 

 lows of the mountain during winter. 



The strips of green herbage and forest 

 land which have here and there escaped the 

 burning lavas serve, by contrast, to heighten 

 the desolation of the scene. When I visited 

 the valley, nine years after the eruption of 

 1819, I saw hundreds of trees, or rather the 

 white skeletons of trees, on the borders of 

 the black lava, the trunks and branches 



being all leafless and deprived of their bark 

 by the scorching heat emitted from the 

 melted rock; an image recalling those beau- 

 tiful lines: 



As when heaven's fire 



Hath scath'd the forest oaks, or mountain pines, 

 With singed top their stately growth, tho bare. 

 Stands on the blasted heath. 



LYELL Principles of Geology, bk. ii, ch. 

 25, p. 405. (A., 1854.)- 



3594. VALLEY PARTITIONED BY 



MEETING DELTAS The separation of 

 lakes Brienz and Thun, Switzerland, has 

 been cited by Davis as an example of the 

 partitioning of a valley by the union of 

 deltas from opposite sides. Interlaken 

 stands on the beautiful alluvial plain thus 

 formed. Several other similar examples in 

 central Europe have been described by vari- 

 ous authors. RUSSELL Lakes af North 

 America, ch. 1, p. 7. (G. & Co., 1895.) 



3595. VALLEYS HOLLOWED BY 

 GLACIERS Ice, Sand, and Water Combine to 

 Wear Away Rocks. In the case of every 

 glacier we have two agents at work the 

 ice exerting a crushing force on every point 

 of its bed which bears its weight, and either 

 rasping this point into powder or tearing 

 it bodily from the rock to which it belongs; 

 while the water which everywhere circulates 

 upon the bed of the glacier continually wash- 

 es the detritus away and leaves the rock 

 clean for further abrasion. Confining the 

 action of glaciers to the simple rubbing away 

 of the rocks, and allowing them sufficient 

 time to act, it is not a matter of opinion, 

 but a physical certainty, that they will scoop 

 out valleys. TYNDALL Hours of Exercise in 

 the Alps, ch. 20, p. 238. (A., 1898.) 



3596. VALUE OF LEAST PROMIS- 

 ING ELEMENT The Layer of Scum and 

 Mud the Most Important Part of Filter. 

 Koch maintained that the portion of the 

 filter - bed which really removed micro- 

 organisms effectively was the slimy organic 

 layer upon the surface. This layer is pro- 

 duced by a deposit from the still unpurified 

 water lying immediately above it. The most 

 vital part of the filter-bed is this organic 

 layer, which, after -formation, should not 

 be disturbed until it requires removal owing 

 to its impermeability. . . . The only vital 

 part of the [filtration] process ... is 

 the chemical effect of the layer of scum and 

 mud on the surface of the sand at the top 

 of the filter-bed. The mechanical part of 

 this layer is, of course, the holding back of 

 the particulate matter which has not sub- 

 sided in the reservoir; the vital action con- 

 sists in what is termed nitrification of un- 

 oxidized substance, which is accomplished 

 in this layer of organic matter. NEWMAN 

 Bacteria, ch. 2, p. 75. (G. P. P., 1899.) 



3597. VALUE OF SIMPLICITY- 



Plain Food Best for Constant Use^-Codftsh 

 Used Like Bread The Bonito of the Medi- 

 terranean. By boiling out the rich oil of 



