66 ( 3 o) 



nomena of the organism to physical and chemical laws depends chiefly 

 (and almost in the same manner as the prediction of meteorological 

 processes in the atmosphere) on the complication of the phenomena, 

 and on the great number of the simultaneously acting forces as well 

 as the conditions of their activity." 



3 Compare HENRY BENCE JONES, Croonian Lectures on Matter 

 and Force. London, 1868, John Churchill & Sons. 



4 Ib., Preface, p. vi. 



5 RANKINE, W. J. M., Philosophical Magazine, Feb., 1853. 

 Also Edinburgh Philosophical Journal, July, 1855. 



6 ARMSTRONG, Sir WM. In his address as President of the 

 British Association for the Advancement of Science. Rep. Brit. 

 Assoc., 1863, li. 



7 GROVE, W. R., in 1842. Compare "Nature" i, 335, Jan. 27, 

 1870. Also Appleton's Journal, iii, 324, Mch. 19, 1870. 



8 Id., in Preface to The Correlation of Physical Forces, 4th ed. 

 Reprinted in The Correlation and Conservation of Forces, edited 

 by E. L. Youmans, p. 7. New York, 1865, D. Appleton & Co. 



9 Id., ib., Am. ed., p. 33 et seq. 



10 JOULE, J. P., Philosophical Transactions, 1850, p. 61. 



11 See American Journal of Science, II, xxxvii, 296, 1864. 



12 The work (W) done by a moving body is commonly expressed 

 "by the formula W=MV 2 , in which M, or the mass of the body, is 



\v 



equal to j /. e., to the weight divided by twice the intensity 



of gravity. The work done by our cannon-ball then, would be 



- - y- =9,404* 1 4 foot-tons. If, further, we assume the re- 

 2X041-3 , 



sisting body to be of such a character as to bring the ball to 

 rest in moving ^ of an inch, then the final pressure would be 

 9,4O4'i4X 12X4=45 1, 3987 tons - B ut since, "in the case of a pre- 

 fectly elastic body, or of a resistance proportional to the advance of 

 the center of gravity of the impinging body from the point at which 

 contact first takes place, the final pressure (provided the body 



