31.2 Prof. Bolm on the Conservation of Energy. 



quantitatem, quam facile intelligimus eandem semper in tota 

 rerum universitate esse posse, quamvis in singulis ejus partibus 

 mutetur. Ita scilicet ut putemus, cum una pars materia duplo 

 celerius movetur, quam altera, et hsec altera duplo major est 

 quam prior, tantundem motus esse in minore quam in majore, 

 ac quantb motus unius partis lentior fit, tanto motum alicujus 

 alterius ipsi sequalis fieri celeriorem. Intelligimus etiam per- 

 fectionem esse in Deo, non solum quod in se ipso sit immu- 

 tabilis, sed etiam quod modo quam maxime constanti et immu- 

 tabili operetur : Adeo ut iis mutationibus exceptis, quas evidens 

 experientia, vel divina revelatio certas reddit, quasque sine ulla 

 in creatore mutatione fieri percipimus, aut credimus, nullas alias 

 in ejus operibus supponere debeamus, ne qua inde inconstantia 

 in ipso arguatur. Unde sequitur quam maxime rationi esse 

 consentaneum, ut putemus ex hoc solo, quod Deus diversimode 

 moverit partes materia?, cum primum illas creavit, jamquetotam 

 istammateriam conservet, eodem plane modo, eademque ratione 

 qua prius creavit, eum etiam tantundem motus in ipsa semper 

 conservare." 



Descartes therefore, precisely like Colding, bases the proof of 

 his theorem on a divine attribute. The ud satisfactory nature of 

 such a proof is manifest. Are we not equally justified in assert- 

 ing that the assumption of a constant quantity of motion involves 

 a limitation of divine power ? The almightiness of God must 

 manifest itself by actual achievement, new motion must inces- 

 santly be created ; therefore, assuming with Descartes the inde- 

 structibility of that which exists, the quantity of motion must 

 increase. 



Every attempt to deduce a natural law from an a priori con- 

 ceived attribute of God must inevitably be utterly fruitless. 



Leibnitz was the first to publish, in its proper form, the general 

 theorem of the conservation of vis viva, and to demonstrate 

 the same by empirically ascertained and rationally established 

 theorems. He at once opposes Descartes's views, and introduces 

 the important conception of vis viva. All this will be found in 

 his article in the Acta Eruditorum, Lips. 1686, entitled : " Brevis 

 demonstrate erroris memorabilis Cartesii et aliorum circa legem 

 naturse, secundum quam volunt a Deo eandem semper quantita- 

 tem motus conservari, qua et in re mechanica abutuntur." 



In the warm discussion which arose, Leibnitz argued that the 

 assumption of the incorrectness of his views involved the neces- 

 sity, or at least the possibility of a perpetual motion ; which lat- 

 ter he urged is manifestly absurd. Colding employs the same 

 argument ; and Helmholtz, in 1847, in his well-known work ' On 

 the Conservation of Force/ attributes great importance to this 

 theorem concerning the absurdity of perpetual motion. 



