p?, 



wer 

 'rayer 



SCIENTIFIC SIDE-LIGHTS 



546 



and philosophy combine together in one per- 

 son, then, indeed, we have the highest sort of 

 intellectual efficiency. Your Walter Scotts, 

 your Leibnitzes, your Gladstones, and your 

 Goethes, all your folio copies of mankind, 

 belong to this type. Efficiency on a colossal 

 scale would indeed seem to require it. For, 

 altho your philosophic or systematic mind 

 without good, desultory memory may know 

 how to work out results and recollect where 

 in the books to find them, the time lost 

 in the searching process handicaps the 

 thinker, and gives to the more ready type 

 of individual the economical advantage. 

 JAMES Talks to Teachers, ch. 12, p. 120. 

 (H. H. & Co., 1900.) 



2692. POWER STORED IN COAL- 

 FIELDS Millions of Horses Could Not Equal. 

 We dig annually 84 millions of tons of 

 coal from our pits. The amount of mechan- 

 ical force represented by this quantity of 

 coal seems perfectly fabulous. The combus- 

 tion of a single pound of coal, supposing it 

 to take place in a minute, would be equiva- 

 lent to the work of 300 horses; and if we 

 suppose 108 millions of horses working day 

 and night with unimpaired strength for a 

 year, their united energies would enable 

 them to perform an amount of work just 

 equivalent to that which the annual produce 

 of our coal-fields would be able to accom- 

 plish. TYNDALL Fragments of Science, vol. 

 i, ch. 16, p. 373. (A., 1897.) 



2693. POWER UNDESIRABLE WITH- 

 OUT BENEFICENCE A cold and inert 

 mass of matter, however, would be able to 

 do all that the sun does by his mere mass, 

 and yet be utterly unfit to be, like him, the 

 ruler over a scheme of circling worlds. The 

 glory of the sun is not in his strength alone. 

 As Sir John Herschel has well said, " Giant 

 size and giant strength are ugly qualities 

 without beneficence." But the sun is the 

 almoner of the Almighty, the delegated dis- 

 penser to us of light and warmth, as well 

 as the center of attraction. PROCTOR Ex- 

 panse of Heaven, ch. 2, p. 15. (L. G. & Co., 

 1897.) 



2694. POWERS, MECHANICAL, ALL 

 USED BY PRIMITIVE MAN The mechan- 

 ical powers, in the order of their simplicity, 

 are the inclined plane, the wedge, lever, the 

 roller, the pulley, the wheel and axle, and 

 the screw. These devices for converting time 

 and weight and velocity into momentum, 

 and for changing the direction and character 

 of momentum, are at the foundation of the 

 modern intricate machinery. But the sim- 

 plest forms of all these useful things were 

 elaborated by primitive mechanics with what 

 little suggestion they could get from the 

 animal world. The inclined plane, both for 

 rolling and sliding friction, as well as for 

 convenience in walking, is too easy to dwell 

 upon. The Eskimo sledge men, the hunter 

 dragging his game, the fishermen on a slo- 

 ping beach landing a great sea monster or a 



canoe, the Indians of the canons making a 

 trail, the Caribs launching a pirogue, the 

 mound-builders or the Mexicans ascending 

 a great ceremonial earthwork, were equally 

 skilled in selecting a gentle slope or in ma- 

 king one. The natives of British Columbia 

 make skids of stout saplings, and on them 

 roll up the logs that are to form the plate 

 pieces of their communal dwellings, holding 

 them in position by means of shore poles. 

 The great stone buildings of Mexico, Central 

 America, and Peru were the work of men's 

 hands, with no aid from animals or nat- 

 ural powers. The invariable association of 

 all such structures with sloping earthworks 

 and pyramids points to the chief mechanic- 

 al power known to the builders. An addi- 

 tional value is given to the inclined plane 

 in that it allows the cooperation of as many 

 individuals as are necessary, and it also 

 lends itself to cooperation with the other 

 powers. The wedge was in universal use 

 among the American native mechanics. . . . 

 The wedges were always made of the hard- 

 est material known in any region. Wood, 

 ivory, elkhorn, bone, and even hammered 

 copper did service. ~M,Aso?f Aboriginal Amer- 

 ican Mechanics (Memoirs of the Internation- 

 al Congress of Anthropology, p. 74). (Sch. 

 P. C.) 



2695. POWERS, MECHANICAL, AN- 

 TEDATE HISTORY The Lever, Roller, In- 

 dined Plane, and Pulley Known in Ancient 

 Egypt. As to how simple mechanical pow- 

 ers were first learned, it is of no use to 

 guess in what rude and early age men found 

 that stones or blocks too weighty to lift 

 by hand could be prized up and moved along 

 with a stout stick, or rolled on two or three 

 round poles, or got up a long, gentle slope 

 more easily than up a short, steep rise. Thus 

 such discoveries as those of the lever, roller, 

 and inclined plane are quite out of historical 

 reach. The ancient Egyptians used wedges 

 to split off their huge blocks of stone, and 

 one wonders that, knowing the pulleys as 

 they did, it never appears in the rigging of 

 their ships. ... A draw-well, with a 

 pulley, is to be seen in the Assyrian sculp- 

 tures, where also a huge winged bull is being 

 heaved along with levers, and dragged on a 

 sledge with rollers laid underneath. TYLOR 

 Anthropology, ch. 8, p. 198. (A., 1899.) 



2696. POWERS, UNUSED, PERISH 



The Eyes of the Mole Atrophied Blind 

 Fishes in Caves. There are certain bur- 

 rowing animals the mole, for instance 

 which have taken to spending their lives 

 beneath the surface of the ground. And 

 Nature has taken her revenge upon them in 

 a thoroughly natural way she has closed 

 up their eyes. If they mean to live in dark- 

 ness, she argues, eyes are obviously a super- 

 fluous function. By neglecting them these 

 animals made it clear they do not want 

 them. And as one of Nature's fixed prin- 

 ciples is that nothing shall exist in vain, 

 the eyes are presently taken away, or re- 



