451 



SCIENTIFIC SIDE-LIGHTS 



Mind 

 Minerals 



or Taine these resolve themselves at last 

 into little elementary psychic particles or 

 atoms of " mind-stuff," out of which all the 

 more immediately known mental states are 

 said to be built up. Locke introduced this 

 theory in a somewhat vague form. Simple 

 " ideas " of sensation and reflection, as he 

 called them, were for him the bricks of 

 which our mental architecture is built up. 

 . . . Whether it be true or false, it is 

 at any rate only conjectural; and, for 

 practical purposes, the more unpretending 

 conception of the stream of consciousness, 

 with its total waves or fields incessantly 

 changing, will amply suffice. JAMES Talks 

 to Teachers, ch.2, p. 19. (H. H. & Co., 1900.) 



20 1O. MIND UNLIKE THE HUMAN 

 UNKNOWN TO THE HUMAN If it can 

 be said with truth that " the universal mind 

 is essentially other than the human mind," 

 so that no recognizable relations can exist 

 between them, then that universal mind is 

 to us as if it were not. ARGYLL Reign of 

 Law, ch. 2, p. 63. (Burt.) 



2211. MIND, UNTRAINED, PREFERS 

 THE MARVELOUS TO THE TRUE Won- 

 derful and Terrible Agencies Excite Super- 

 stition. It is not difficult to understand 

 how false notions on the subject of volcanic 

 action have come to be so generally preva- 

 lent. In the earlier stages of its develop- 

 ment, the human mind is much more con- 

 genially employed in drinking in that which 

 is marvelous than in searching for that 

 which is true. It must be admitted, too, 

 that the grand and striking phenomena dis- 

 played by volcanoes are especially calculated 

 to inspire terror and to excite superstition, 

 and such feelings must operate in prevent- 

 ing those close and accurate observations 

 \\hich alone can form the basis of scientific 

 reasoning. JTJDD Volcanoes, ch. 1, p. 2. (A., 

 1899.) 



2212. MIND WELL FURNISHED IS 

 CAPABLE OF SUSTAINED ATTENTION 

 We can see why it is that what is called 

 sustained attention is the easier, the rich- 

 er in acquisitions and the fresher and 

 more original the mind. In such minds, 

 subjects bud and sprout and grow. At 

 every moment, they please by a new conse- 

 quence and rivet the attention afresh. But 

 an intellect unfurnished with materials, 

 stagnant, unoriginal, will hardly be likely 

 to consider any subject long. A glance ex- 

 hausts its possibilities of interest. Geniuses 

 are commonly believed to excel other men in 

 their power of sustained attention. In 

 most of them, it is to be feared, the so- 

 called " power " is of the passive sort. Their 

 ideas coruscate, every subject branches in- 

 finitely before their fertile minds, and so for 

 hours they may be rapt. JAMES Psychology, 

 vol. i, ch. 11, p. 423. (H. H. & Co., 1899.) 



2213. MINERALS HELD INVISIBLE 

 IN WATER Calcareous Substances Deposited 

 by Boiling Opposite Results of a Single 

 Process. Spring-water and river-water that 



have passed through or over considerable 

 distances in calcareous districts suffer 

 change in boiling. The origin and nature 

 of this change may be shown by an experi- 

 ment as follows : Buy a pennyworth of lime- 

 water from a druggist and procure a small 

 glass tube of about quill size, or the stem of 

 a fresh tobacco-pipe may be used. Half fill 

 a small wine-glass with the lime-water, and 

 blow through it by menus of the tube or 

 tobacco-pipe. Presently it will become tur- 

 bid. Continue the blowing, and the turbid- 

 ity will increase up to a certain degree of 

 .milkiness. Go on blowing with " commend- 

 able perseverance," and an inversion of ef- 

 fect will follow; the turbidity diminishes, 

 and at last the water becomes clear again. 



The chemistry of this is simple enough. 

 From the lungs a mixture of nitrogen, 

 cxygen, and carbonic acid is exhaled. The 

 carbonic acid combines with the soluble lime, 

 and forms a carbonate of lime, which is in- 

 soluble in mere water. But this carbonate 

 of lime is to a certain extent soluble in 

 water saturated with carbonic acid, and 

 such saturation is effected by the continu- 

 ation of blowing. 



Take some lime-water that has been thus 

 treated, place it in a clean glass flask, and 

 boil it. After a short time the flask will be 

 found incrusted with a thin film of some- 

 thing. This is the carbonate of lime which 

 has been thrown down again by the action 

 of boiling, which has driven off its solvent, 

 the carbonic acid. This crust will effervesce 

 if a little acid is added to it. WILLIAMS 

 Chemistry of Cookery, ch. 2, p. 10. (A., 

 1900.) 



2214. MINERALS OF VESUVIUS 



A great variety of minerals are found in the 

 lavas of Vesuvius and Somma; augite, 

 leucite, feldspar, mica, olivin, and sulfur are 

 most abundant. It is an extraordinary fact 

 that in an area of three square miles round 

 Vesuvius a greater number of simple min- 

 erals have been found than in any spot of 

 the same dimensions on the surface of the 

 globe. Hauy enumerated only 380 species of 

 simple minerals as known to him; and no 

 less than eighty-two had been found on Ve- 

 suvius and in the tuffs on the flanks of 

 Somma before the end of the year 1828. 

 Many of these are peculiar to that locality. 

 Some mineralogists have conjectured that 

 the greater part of these were not of Vesu- 

 vian origin, but thrown up in fragments 

 from some older formation, through which 

 the gaseous explosions burst. But none of 

 the older rocks in Italy or elsewhere con- 

 tain such an assemblage of mineral prod- 

 ucts ; and the hypothesis seems to have been 

 prompted by a disinclination to admit that, 

 in times so recent in the earth's history, the 

 laboratory of Nature could have been so 

 prolific in the creation of new and rare com- 

 pounds. Had Vesuvius been a volcano of 

 high antiquity, formed when Nature 



Wantpn'd as in her prime, and play'd at will 

 Her virgin fancies, 



