1846] WRITINGS OF JOSEPH HENRY. 255 



ON THE ATOMIC CONSTITUTION OF MATTER. 



(Proceedings of the American Philosophical Society, vol. iv, pp. 287-290.) 

 November 6. 1846. 



The reference to a paper presented at the preceding meet- 

 ing of the Society led Professor Henry to make some remarks 

 on the corpuscular hypothesis of the constitution of matter. 



He stated that this subject has occupied attention at every 

 period of the history of science, and though at first sight 

 speculations of this kind might appear to belong exclusively 

 to the province of the imagination, yet in reality he con- 

 sidered this hypothesis a fruitful source of valuable additions 

 to our knowledge of the actual phenomena of the physical 

 world. Though simple insulated facts may occasionally be 

 stumbled upon by a lucky accident, the discovery of a series 

 of facts or of a general scientific principle is in almost all 

 cases the result of deductions from a rational antecedent 

 hypothesis, the product of the imagination — founded it is true 

 on a clear analogy with modes of physical action the truth 

 of which have been established by previous investigation. 



In constructing an hypothesis of the constitution of matter 

 the simplest assumption, and indeed the onl}' one founded on 

 a proper physical analogy, is that the same laws of force and 

 motion which govern the phenomena of the action of matter 

 in masses pertains to the minutest atoms of these masses. 



It is a well established fact that portions of matter at a 

 distance tend to approach each other, and when they are 

 brought very near, to separate, and still nearer, again to 

 approach, and so on through several alternations. In the 

 present state of science we consider these actions as ultimate 

 facts to which we give the name of attracting and repelling 

 forces, and without attempting to go behind them we may 

 study their laws of variation as to intensity and direction 

 under different circumstances and particularly in reference 

 to a change of distance. Bodies or masses of matter are also 

 subjected to fixed laws of motion which have been classed 



