114 



Article IV. 



On the Conservation of Force ; a Physical Memoir. 

 By Dr. H. Helmholtz. 



[Read before the Physical Society of Berlin on the 23rd of July, 1847. 

 Berlin. G. Reimer.] 



Contents. 



Introduction. 

 I. The principle of the Conservation of vis viva, 

 II. The principle of the Conservation of Force. 



III. The application of the principle in Mechanical Theorems. 



IV. The Force-equivalent of Heat. 



V. The Force-equivalent of the Electric Processes. 

 VI. The Force-equivalent of Magnetism and Electro-magnetism. 



Introduction. 



1 HE principal contents of the present memoir show it to be 

 addressed to physicists chiefly, and I have therefore thought it 

 judicious to lay down its fundamental principles purely in the 

 form of a physical premise, and independent of metaphysical 

 considerations, — to developethe consequences of these principles, 

 and to submit them to a comparison with what experience has 

 established in the various branches of physics. The deduction 

 of the propositions contained in the memoir may be based on 

 either of two maxims ; either on the maxim that it is not possible 

 by any combination whatever of natural bodies to derive an 

 unlimited amount of mechanical force, or on the assumption that 

 all actions in nature can be ultimately referred to attractive or 

 repulsive forces, the intensity of which depends solely upon the 

 distances between the points by which the forces are exerted. 

 That both these propositions are identical is shown at the com- 

 mencement of the memoir itself. Meanwhile the important 

 bearing which they have upon the final aim of the physical 

 sciences may with propriety be made the subject of a special 

 introduction. 



The problem of the sciences just alluded to is, in the first 

 place, to seek the laws by which the particular processes of 



