166 NEWTON AND DAVY. 



What then is the internal constitution of mat- 

 ter ? Are the pores of bodies void of all sub- 

 stance ? or are they pervaded by subtile and 

 active matter ? If so, what is it, and what are 

 the laws by which it operates ? It is quite cer- 

 tain, that until these important queries are re- 

 solved, the science of nature can never be 

 established on the solid rock of first principles ; 

 but must remain, as heretofore, imperfect and 

 vacillating.* 



It requires no extended series of argument to 

 prove, that whatever the cause may be which 

 moves atoms, must also be the cause which moves 

 the largest bodies, for the simple and obvious 



* It was supposed by Epicurus and his followers, that " the 

 atoms of fluids were smooth and spherical, by which they were 

 enabled to glide freely over each other ; but that the atoms of 

 solids were hooked/' as if their forms could change on passing 

 from the liquid to the solid state. He also maintained that the 

 pores of bodies were void of all matter. (De Natura Rerum, 

 book ii.) Others have supposed that the particles of bodies are 

 glued together by an immaterial cement, as bricks are held 

 together by mortar. (Baxter on the Immateriality of the Soul.) 

 The Rev. W. Jones referred cohesion to the pressure of a cold 

 ather y from the fact that liquids are converted into solids by 

 cold. This he thought was demonstrated by the expansion of 

 water during the process of freezing ; an effect which is obviously 

 owing to the arrangement of its particles in the crystalline form. 

 Ampere, Berzelius, and some other modern philosophers have 

 maintained that the atoms of bodies are endowed with electric 

 polarity, or that their opposite sides are in different states of 

 electricity ; while the great body of chemists regard the whole 

 subject as involved in profound obscurity. 



