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can be referred to one or more of these laws, it follows that any cor- 

 puscular hypothesis which does not ascribe to each atom of matter 

 the property of obedience to the same laws, must be defective. It 

 was for this reason, said Professor H., that in printing a syllabus of 

 my lectures, about two years ago, I was induced to make some addi- 

 tions to the assumptions on which the corpuscular hypothesis of Bos- 

 covich is founded. According to this celebrated hypothesis, a portion 

 of matter consists of an assemblage in space of an indefinite number 

 of points kept at a given distance by attracting and repelling forces. 

 These points have relative position, but not magnitude, and are 

 merely centres of action of the forces which affect our senses ; and 

 since all our knowledge of matter is derived from the action of these 

 forces, to infer that these points are any thing more than the centres 

 of forces, is going beyond our premises. 



This hypothesis readily explains the statical properties of bodies, 

 such as elasticity, porosity, impenetrability, solidity, liquidity, crys- 

 tallization, resistance to compression when a force is applied to either 

 side of a body, &c. ; but it fails to account for the dynamic pheno- 

 mena of masses of matter, or those which are referrible to the three 

 laws of motion. It is not, therefore, enough, that we assume, as the 

 elements of matter, an assemblage of points in space, from which 

 merely emanate attracting and repelling forces; we must also sup- 

 pose these points to be endowed with inertia, or a tendency to resist 

 a change of state, whether of rest or motion, and a tendency to move 

 in a straight line; also to possess the property of preserving the 

 effects of a number of impulses, as well as that of transferring motion 

 from one point to another, the one losing as much motion as the 

 other gains. But the admission of the existence of points with such 

 qualities, brings us back to the Newtonian hypothesis of matter. 



According to the view we have given, a portion of matter consists 

 of an assemblage of indivisible and indestructible atoms endowed with 

 attracting and repelling forces, and with the property of obedience to 

 the three laws of motion. All the other properties, and indeed all the 

 mechanical phenomena of matter, so far as they have been analyzed, 

 are probably referrible to the action of such atoms, arranged in 

 groups of different orders, namely, of ultimate atoms, chemical atoms, 

 simple molecules, compound molecules, particles, &c. ; the distance 

 in all cases, between any two atoms, being much greater than the 

 diameter of the atoms or molecules. 



In order that we may bring the phenomena of the imponderable 

 agents of nature, as they are called, under the category of the laws 



