THE TABLE OF THE LAW. 29 



This periodic law of the atoms is God's alphabet of the 

 universe. By means of it, and by means of it only, can 

 we ever hope to spell out the history and the future of 

 creation. It lies here before us lacking only the master 

 word the open sesame to creation; and, who knows, to 

 the Creator, too? If the system were regular, completely 

 symmetrical, we should either understand the mystery 

 that is, there would be an end of the mystery altogether 

 or we should forever be beyond the hope of solving it. But 

 the delight of it is, and the hope of it lies in its regular irreg- 

 ularity. Leaving for the moment the whims and caprices of 

 the law that constitute its irregularities, let us turn, first, to 



THE REGULARITIES OF THE LAW. 



A glance at the table (Fig. 5) will inform the reader that 

 each of the elements of matter has a little compartment of 

 its own in the table. This compartment belongs to it, and 

 the element will refuse to go anywhere else. 



To demonstrate this, we may fix our attention upon any 

 one element and consider it in its relation to the other ele- 

 ments which lie either msi horizontal or in a vertical line with it. 



The elements which lie horizontally with reference to any 

 given element are called a series; those which lie vertically, 

 a group. 



The actual position of any one element in the table is fixed 

 solely by the weight of its atom ; and once so fixed, its other 

 properties follow as a matter of necessity from its series and 

 group relations. 



The elements in any one series vary by definite steps, but 

 they are sharply differentiated from one another; and in 

 spite of their progressive variations from one side of the 

 table to the other, they are of different types. The ele- 

 ments, of a group vary progressively from top to bottom, but 



