130 The Rev. J. Bay ma on Molecular Mechanics, [Feb. 11, 



mechanics, of which it would be impossible to treat at all, unless the law 

 of elementary action at infinitesimal distances were known. This truth 

 universalizes Newton's law of celestial attraction by extending it to all 

 elementary action, whether attractive or repulsive, and makes it applicable 

 not only to telescopic, but also to microscopic distances. It is clear there- 

 fore that I am bound to prove this law most irrefragably, lest I construct 

 my molecular mechanics on an insecure foundation. 



4. The sphere of the activity of matter is indefinite, in this sense, that 

 no finite distance can be assigned at which the action of matter will be null. 

 It by no means, however, follows from this that the force of matter has an 

 infinite intensity. 



5. The natural activity of each element of matter is exerted immediately 

 on every other existing element at any distance, either by attracting or 

 repelling, according to the agent's nature. Thus, e, g.y the action which 

 the earth exerts on each falling drop of rain is exerted immediately by each 

 element of the earth on each element of the water (notwithstanding the dis- 

 tance between them) ; it is not exerted through the material medium of the 

 air, or of ether, or any other substance. The same must be said of the action 

 of the sun on the planets. This proposition, however, it is evident, holds 

 only for the simple action of the elements, i. e., attractive or repulsive. 

 For it is clear that complex actions causing vibratory motions, such as 

 light or sound, are only transmitted through some vibrating medium. This 

 conclusion is also of immense importance, because it solves a question much 

 discussed by the ancients about the nature of action exerted on a distant 

 body, and removes all scruples of philosophers on this head. 



6. Bodies do not and cannot act by mathematical contact, however 

 much our prejudices incline us to think the contrary ; but every material 

 action is always exerted on something at a distance from the agent. 



7. There is another prejudice which I wish to remove, i. e. that one 

 motion is the efficient cause of another motion. It is easily shown that 

 this mode of speaking, though sometimes employed by scientific men, is 

 incorrect, and ought to be abandoned, because it tends to the destruction 

 of all natural science. Motion never causes motion, but is only a condition 

 affecting the agent in its manner of acting. For all motion is caused by 

 some agent giving velocity and direction ; but the agent gives velocity and 

 direction by means of its own active power, which it exerts differently 

 according as it is found in different local conditions. Now these local 

 conditions of the agent may be differently modified by the movement of 

 the agent itself. The impact of bodies, the change of motion to heat, the 

 communication of velocity from one body to another (always a difficult 

 question), and other points of a like nature can only be satisfactorily 

 explained by this principle. 



These are the principal points that have to be discussed, defined, and 

 demonstrated in order that molecular mechanics may be established on 

 solid principles. 



