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BIGELOW. 
chanical system is ignored or thrown out of consideration, 
and the kinetic potential is alone employed; (2) the change 
in kinetic energy is assumed to he equal to the change in 
the energy of the system. In a word, all energy is kinetic, 
and no energy is potential—that is, after all the grand change 
from the mechanical system to the energy system of treatment. 
Lagrange made it possible by his equation; Maxwell first rec¬ 
ognized the importance and necessity of this reformation, and 
out of it came his splendid electric and magnetic equations; 
Helmholtz adopted the same plan and found the laws of the 
cyclic and reciprocal system; Hertz , in his great treatise on 
modern mechanics, excludes the potential energy from his 
system; J. J. Thomson has successfully applied this method 
to a great number of physical problems, and he says, “ We 
may look upon the potential energy of any system as kinetic 
energy arising from the motion of systems connected with 
the original system, and from this point of view all energy 
is kinetic, and all terms in the Lagrangian function express 
kinetic energy, the only thing doubtful being whether the 
kinetic energy is due to the motion of ignored or positional 
coordinates” (Dynamical Methods, p. 14). Poincare states, “ I 
have demonstrated that the principles of thermodynamics 
are incompatible with mechanical principles of direct action 
and action at a distance; also mechanism is incompatible 
with the theorem of Clausius. ” Helm makes a long argu¬ 
ment in favor of the view that energy transformations 
cannot be explained by mechanical analysis of the most 
advanced type. All this applies to the type of reversible or 
cyclic processes; but in the case of the irreversible or acyclic 
phenomena, even this law of Clausius is not available, for 
Poincare states (Thermodynamique, p. 422), “ it results from 
this that irreversible phenomena and the theorem of Clau¬ 
sius are not explicable by means of Lagrange’s equations.”' 
In a word, the first law of thermodynamics may have some 
mechanical analogues, but in connection with the second 
law there are no such analogues from mechanics. Heaviside 
has made a very stout effort to secure such analogues for 
