Fffli 



stence 



SCIENTIFIC SIDE-LIGHTS 



520 



eter, within which the gladiator Spartacus 

 and his followers were besieged by a Roman 

 army. There is no evidence that at this 

 time the volcanic character of the mountain 

 was generally recognized, and its slopes are 

 described by the ancient geographers as be- 

 ing clothed with fertile fields and vineyards, 

 while the hollow at the top was a waste 

 overgrown with wild vines. 



But in the year 79 a terrible and unex- 

 pected eruption occurred, by which . . . 

 the cities of Pompeii, Herculaneum, and 

 Stabise were overwhelmed and buried. 

 JUDD Volcanoes, ch. 4, p. 83. (A., 1899.) 



2559. PERILS OF THE SNOW Trav- 

 eler's Sense of Direction Destroyed ~by Swirl- 

 ing Eddies. Snow is not always our 

 friend. ... In thinly inhabited coun- 

 tries there is no greater danger than to be 

 overtaken by a heavy fall of snow or caught 

 in storms of snow-dust, raised from ground 

 on which snow has previously fallen and 

 whirled along by the wind. In such cases 

 one's only safety is to make at once for the 

 nearest human dwelling in sight. If there 

 is none in sight, the danger of being lost is 

 great, for nothing so destroys one's sense of 

 direction as the confused eddies of falling 

 snow or swirling snow-dust. CHISHOLM 

 Nature-Studies, p. 31. (Hum., 1888.) 



2560. PERMANENCE, APPARENT 



Mountain Seems Eternal A First View of 

 the Matterhorn. Above us rise the towers 

 and pinnacles of the Matterhorn, certainly 

 a tremendous array. Actual contact im- 

 mensely increases one's impressions of this, 

 the hardest and strongest of all the moun- 

 tain masses of the Alps; its form is more 

 remarkable than that of other mountains, 

 not by chance, but because it is built of 

 more massive and durable materials, and 

 more solidly put together: nowhere have I 

 seen such astonishing masonry. The broad 

 gneiss blocks are generally smooth and com- 

 pact, with little appearance of splintering 

 or weathering. Tons of rock, in the shape 

 of boulders, must fall almost daily down 

 its sides, but the amount of these, even 

 in the course of centuries, is as nothing 

 compared with the mass of the mountain; 

 the ordinary processes of disintegration can 

 have little or no effect on it. If one were to 

 follow Mr. Ruskin, in speculating on the 

 manner in which the Alpine peaks can have 

 assumed their present shape, it seems as if 

 such a mass as this can have been blocked 

 out only while rising from the sea, under 

 the action of waves such as beat against the 

 granite headlands of the Land's End. Once 

 on dry land it must stand as it does now, 

 apparently forever. HAWKINS in TYN- 

 DALL'S Hours of Exercise in the Alps, ch. 3, 

 p. 39. (A., 1898.) 



2561. Transition Unper- 



ceived Changing Cloud on Mountain Peak. 

 You frequently see a streamer of cloud 

 many hundred yards in length drawn out 

 from an Alpine peak. Its steadiness ap- 



pears perfect, tho a strong wind may be 

 blowing at the same time over the mountain- 

 head. Why is the cloud not blown away? 

 It is blown away; its permanence is only 

 apparent. At one end it is incessantly dis- 

 solved, at the other end it is incessantly re- 

 newed: supply and consumption being thus 

 equalized, the cloud appears as changeless 

 as the mountain to which it seems to cling. 

 When the red sun of the evening shines 

 upon these cloud streamers they resemble 

 vast torches with their flames blown 

 through the air. TYNDALL Forms of Water, 

 p. 29. (A., 1899.) 



2562. PERMANENCE OF CONCEP- 

 TIONS Change of Conceptions Is Not Altera- 

 tion,but Substitution. Each conception thus 

 eternally remains what it is, and never can 

 become another. The mind may change its 

 states and its meanings at different times, 

 may drop one conception and take up an- 

 other, but the dropped conception can in no 

 intelligible sense be said to change into its 

 successor. The paper, a moment ago white, 

 I may now see to have been scorched black. 

 But my conception " white " does not 

 change into my conception " black." On the 

 contrary, it stays alongside of the objective 

 blackness, as a different meaning in my 

 mind, and by so doing lets me judge the 

 blackness as the paper's change. Unless it 

 stayed, I should simply say " blackness " 

 and know no more. Thus, amid the flux of 

 opinions and of physical things, the world 

 of conceptions, or things intended to be 

 thought about, stands stiff and immutable, 

 like Plato's "Realm of Ideas." JAMES 

 Psychology, vol. i, ch. 12, p. 432. (H. H. & 

 Co., 1899.) 



2563. PERMANENCE OF LEVEL OF 

 SWISS LAKES Extends at Least to the 

 Bronze Age. As piles [in the remains of 

 Swiss lake-dwellings] of the Bronze Age 

 are sometimes found at a depth of as much 

 as fifteen feet, and as it is manifest that 

 buildings cannot have been constructed over 

 water much deeper than this, it is evident 

 that the Swiss lakes cannot then have stood 

 at a much higher level than at present. 

 This conclusion is confirmed by the position 

 of Roman remains at Thonon, on the Lake 

 of Geneva, and we thus obtain satisfactory 

 evidence that the height of the Swiss lakes 

 must have remained almost unaltered for a 

 very long period. AVEBURY Prehistoric 

 Times, ch. 6, p. 17C. (A., 1900.) 



2564. PERPLEXITIES OF ETYMOLO- 

 GY Children Generalize from Different Start- 

 ing-points " Moon " and " Star " So the 

 Savage Children of the World. Examples 

 of generalization among children abound in 

 every nursery. A child is taken to the win- 

 dow by his nurse to see the moon. The easy 

 monosyllable is caught up at once, and^for 

 some time the child applies it indiscrimi- 

 nately to anything bright or shining the 

 gas, the candle, the firelight are each " the 

 moon." Mr. Romanes records a case where a 



