y8 Mr. Henry Wilde on the 



In table A, it will be seen that the elements on the hori- 

 zontal lines have the same initial letter, with a difference of 

 7 between them, and represent families of elements possess- 

 ing analogous properties, as in the alkaline, and alkaline- 

 earth, metals. This ideal representation of recurring 

 properties at the eighth element has been termed by New- 

 lands the law of octaves, and by Mendeleeff the periodic law. 

 If, however, a new element x be brought into the system, 

 i between B2 and C3, for instance, as shown in table B, the 

 order of the whole system vanishes; as x, by displacing all 

 the elements below it, transposes the family of G from the 

 bottom to the top of the series. The family of G, in its 

 turn, would displace all the other families one step lower 

 down in the table, and thereby transpose them into the next 

 series with a higher order of quantivalence. 



The system would be further disorganised if new 

 elements x, were inserted in other parts of the table, as 

 between B16, C17, and C24, D25, corresponding to the 

 positions of scandium and germanium. 



That a natural classification of elementary substances 

 should rest on foundations so precarious as those above 

 indicated, is a priori extremely improbable. The value of 

 the classifications of Newlands and Mendeleeff must, there- 

 fore, be sought for on other grounds. 



A comparison of Newlands' table of octaves with the 

 atomic weights of the elements, so far as they are known, 

 will show that, the apparent recurrence of elements of the 

 same series, on the same horizontal line, is not so much a 

 consequence of placing them in the regular order of their 

 atomic weights, as the result of an arbitrary arrangement, 

 founded on a chemist's knowledge of the analogous properties 

 of these elements. This is abundantly evident in his table, 

 wherein it has been found necessary (1) to transpose the 

 order of Cr Ti, Ce Zr, U Sn. Te I, Hg Bi Os ; (2) that 

 when elements have about the same atomic weights, one of 



