Energy 

 Enjoyment 



SCIENTIFIC SIDE-LIGHTS 



208 



wheels of the watch move, this is gradually 

 converted into energy of motion. STEWART 

 The Conservation of Energy, ch. 2, p. 377. 

 (Hum., 1880.) 



1O16. 



Water-wheel vs. 



Windmill Accumulated Power Gives Inde- 

 pendence Analogy of Official or Social Po- 

 sition or Wealth in Human Life. It is, in 

 fact,- the fate of all kinds of energy of posi- 

 tion to be ultimately converted into energy 

 of motion. 



The former may be compared to money in 

 a bank, or capital, the latter to money which 

 we are in the act of spending; and just as, 

 when we have money in a bank, we can draw 

 it out whenever we want it, so, in the case 

 of energy of position, we can make use of 

 it whenever we please. To see this more 

 clearly, let us compare together a water-mill 

 driven by a head of water and a windmill 

 driven by the wind. In the one case we may 

 turn on the water whenever it is most con- 

 venient for us, but in the other we must wait 

 until the wind happens to blow. The former 

 has all the independence of a rich man ; the 

 latter all the obsequiousness of a poor one. 

 If we pursue the analogy a step further, we 

 shall see that the great capitalist or the 

 man who has acquired a lofty position is 

 respected because he has the disposal of a 

 great quantity of energy; and that whether 

 he be a nobleman or a sovereign or a gen- 

 eral in command, he is powerful only from 

 having something which enables him to 

 make use of the services of others. When 

 the man of wealth pays a laboring man to 

 work for him, he is in truth converting so 

 much of his energy of position into actual 

 energy, just as a miller lets out a portion of 

 his head of water in order to do some work 

 by its means. STEWART Conservation of 

 Energy, ch. 2, p. 378. (Hum., 1880.) 



1O17. ENERGY OF SUN Seemingly 

 Undiminished Immutability in the Midst 

 of Change. Multiplying all our powers by 

 millions of millions, we do not reach the 

 sun's expenditure. And still, notwithstand- 

 ing this enormous drain, in the lapse of 

 human history we are unable to detect a 

 diminution of his store. Measured by our 

 largest terrestrial standards, such a reser- 

 voir of power is infinite ; but it is our privi- 

 lege to rise above these standards, and to re- 

 gard the sun himself as a speck in infinite 

 extension a mere drop in the universal sea. 

 We analyze the space in which he is im- 

 mersed, and which is the vehicle of his 

 power. We pass to other systems and 

 other suns, each pouring forth energy like 

 our own, but still without infringement of 

 the law, which reveals immutability in the 

 midst of change, which recognizes incessant 

 transference or conversion, but neither final 

 gain nor loss. The energy of Nature is a con- 

 stant quality, and the utmost man can do 

 in the pursuit of physical truth, or in the 

 applications of physical knowledge, is to 

 shift the constituents of the never-varying 



total, sacrificing one if he would produce 

 another. The law of conservation rigidly 

 excludes both creation and annihilation. 

 Waves may change to ripples, and ripples to 

 waves magnitude may be substituted for 

 number, and number for magnitude as- 

 teroids may aggregate to suns, suns may 

 invest their energy in florae and faunae, and 

 florae and faunae may melt in air the flux 

 of power is eternally the same. It rolls in 

 music through the ages, while the manifesta- 

 tions of physical life, as well as the display 

 of physical phenomena, are but the modula- 

 tions of its rhythm. TYNDALL Heat a Mode 

 of Motion, lect. 17, p. 535. (A., 1900.) 



1018. ENERGY REQUIRED TO HOLD 

 GASES TOGETHER IN WATER Prior 



to experience, no one could suspect that two 

 aeriform substances like oxygen and hydro- 

 gen could be obtained from water, and the 

 discovery of the fact, near the beginning of 

 this century, marks an era in the history of 

 science. And even now, familiar as it is, 

 this truth stands out as one of the most re- 

 markable facts of Nature. Moreover, the 

 wonder becomes still greater when we learn 

 that water yields 1,800 times its volume of 

 the two gases, and that these gases retain 

 their aeriform condition so persistently that 

 mechanical pressure alone cannot reduce 

 them to the liquid condition ; and still more 

 the wonder grows when we learn further 

 that the amount of energy required to de- 

 compose a pound of water into its constitu- 

 ent gases would be adequate to raise a 

 weight of 5,314,200 pounds one foot high; 

 and that, when these gases unite and the 

 water is reproduced, this energy again be- 

 comes active. COOKE New Chemistry, lect. 

 5, p. 114. (A., 1899.) 



1019. ENERGY, SEEMING WASTE 

 OF The Sun's Heat Poured into Empty Space 

 Might Warm Two Thousand Million 

 Globes Like Ours. We have just seen the al- 

 most incomprehensible amount of heat which 

 the sun must send the earth in order to 

 warm its oceans and make green its con- 

 tinents; but how little this is to what 

 passes by us ! The earth as it moves on in 

 its annual path continually comes into new 

 regions, where it finds the same amount of 

 heat already pouring forth; and this same 

 amount still continues to fall into the empty 

 space we have just quitted, where there is no 

 one left to note it, and where it goes on in 

 what seems to us utter waste. If, then, the 

 whole annual orbit were set close wfth globes 

 like ours, and strung with worlds like beads 

 upon a ring, each would receive the same 

 enormous amount the earth does now. But 

 this is not all ; for not only along the orbit, 

 but above and below it, the sun sends its 

 heat in seemingly incredible wastefulness, 

 the final amount being expressible in the 

 number of worlds like ours that it could 

 warm like ours, which is 2,200,000,000. 

 LANGLEY New Astronomy, ch. 4, p. 95. (H. 

 M. & Co., 1896.) 



