1846] WRITINGS OF JOSEPH HENRY. 259 



teras of groups, which are necessary to represent the varied 

 and complicated mechanical and chemical phenomena ex- 

 hibited in the physical changes going on around us. Though 

 he could not at this time attempt to give any details of ap- 

 plication of this hypothesis, he drew attention to one class 

 of facts of which it is important to furnish an expression in 

 the arrangement of the atoms. He alluded to the facts of 

 polarity, or those which exhibit the action of opposite forces 

 at the extremities of molecules or of masses. The north and 

 south poles of two magnets, brought together, neutralize 

 each other ; the attraction of one is balanced by the repul- 

 sion of the other, and the point of junction is without action 

 on a third ferruginous body. In the same manner appar- 

 ently, two chemical elements which enter into combination 

 exhibit a neutralizing effect, which indicates the existence 

 of polar forces in the phenomena of chemical action. Noth- 

 ing however is perceptible of this kind in the effects of gravi- 

 tation ; the action of two particles on each other does not 

 interfere with the action at the same time of these two on 

 any number of other particles. 



In conclusion it should be remembered that the legitimate 

 use of speculations of this kind is not to furnish plausible 

 explanations of known phenomena, or to present old knowl- 

 edge in a new and more imposing dress, but to serve the 

 higher purpose of suggesting new experiments and new phe- 

 nomena, and thus to assist in enlarging the bounds of science 

 and extending the power of mind over matter; and unless 

 the hypothesis can be employed in this way, however much 

 ingenuity may have been expended in its construction, it 

 can only be considered as a scientific romance worse than 

 useless, since it tends to satisfy the mind with the semblance 

 of truth, and thus to render truth itself less an object of 

 desire. 



k 



