THE SPACE RELATIONS OF ATOMS. 491 



the smaller globules of water disintegrate and fill up the 

 interstices between the larger globules, thus forming the 

 salt of the sea. The particles of salt have therefore 

 exactly the shape of the interstices between the spheres of 

 water; i.e., they are shaped like "cubes" and tetrahedra, 

 both with curved sides. This is confirmed by fifty experi- 

 ments on salt. For example, the corners or points of the 

 tetrahedra are nothing but the acids of the salt, and if the 

 points be broken off by heat the remainder is insipid and 

 without acidity. 



This work was published by Swedenborg in 1721. 

 Again, as late as 1777, we find Wenzel proving that the 

 properties of bodies depend on the configuration of their 

 smallest particles. A little later, however, arose the doctrine 

 that difference in the properties of matter is due to essential 

 differences among atoms. Atoms of elements were opposed 

 to the old atoms of matter. It is evident that with the 

 growth of this doctrine the necessity for attributing impor- 

 tance to the space' relations of atoms disappeared. For 

 the first time a state of atomic chaos became an a priori 

 possibility. Difference in properties implied now difference 

 in the nature, not in the arrangement of atoms. In particular 

 the question of the relative weights of the atoms came to 

 the front, and pari passu the question of their relative sizes and 

 positions passed to the rear. It soon came to be admitted 

 that, in general, atoms exist only in groups (molecules), but 

 it remained an open question whether or not there was any 

 definite arrangement within these groups ; whether each 

 atom had a fixed position (or a fixed orbit), or whether un- 

 stable equilibrium, a chaotic state of ever-shifting atoms, 

 prevailed within the molecule. 



The discovery of the first isomers, (AgCNO) n , in 

 1823 by Liebig and Wohler seemed calculated to call 

 attention to this question. And presently Gay-Lussac 

 suggested that difference of properties in bodies containing 

 the same atoms and the same number l of each was due to 



1 That the atoms composing Wohler's cyanate and Liebig's fulminate 

 of silver were not present in the same number in the respective molecules, 

 but only in the same proportion, was not immediately recognised. 



