82 " WILD STONE-AVALANCHES." 



the particles of steam next fall together by condensation 

 into liquid water. The mechanical value of this second 

 act is calculated by multiplying the nine pounds of steam 

 by 966 of latent heat = 8,694 pounds of water heated i 

 of Fah't ; which, reduced to foot-pounds by multiplying 

 by 772 (Joule's standard), we have 6,711,768 foot-pounds 

 as the mechanical value of the mere act of conden- 

 sation. . . . 



" The next great fall of our nine pounds of water is 

 from the state of a liquid to that of solid ice, the mechan- 

 ical standard value of which act is equal to nine hundred 

 and ninety-three thousand five hundred and sixty-four 

 foot-pounds. . . . 



" Thus our nine pounds of water, in its original forma- 

 tion and progress into ice, falls down three great preci- 

 pices, which may be estimated by the fall of a ton weight 

 down the first precipice twenty-two thousand three hun- 

 dred and twenty feet high ; the second, by the fall of a 

 ton down a precipice twenty-nine hundred feet high ; 

 and the third fall, by the descent of a ton down a preci- 

 pice four hundred and ninety-six feet high. . . . 



" The number of foot-pounds of mechanical force de- 

 veloped by the three successive clashings of the one 

 pound of molecules of hydrogen, and eight pounds of 

 molecules of oxygen, is thus estimated by the fall of a 

 ton nearly five miles ; and is equivalent to over fifteen 

 hundred horse-power." 



Overwhelmed by such truly astonishing and 

 " tremendous " mechanical results, the professor 

 finally gives utterance to his astonishment in the 

 following graphic words : 



" I have seen the wild stone-avalanches of the Alps, 

 which thunder down the precipices with a vehemence 

 almost sufficient to stun the observer. I have also seen 



