456 HISTORICAL INTRODUCTION TO CHEMISTRY CHAP. 



Law, p. 8). This missing element ( Mendel eeffs eka-silicon) 

 was discovered in 1886 by Winkler, who called it Germanium. 

 (4) " Palladium and platinum appear to be the extremities 

 of a triad, the mean of which is unknown," and remains 

 unknown at the present day. 



Newlands's " Law of Octaves " (1865). To Newlands 

 belongs also the credit of publishing, in 1864, the first table 

 in which the elements were arranged in the order of their 

 atomic weights, and of assigning to the elements thus arranged 

 a series of consecutive atomic numbers (Periodic Law, pp. 7 

 and n). When this arrangement was made, it was seen 

 that: 



"The numbers of analogous elements generally differ 

 either by seven or by some multiple of seven ; in other words, 

 members of the same group stand to each other in the same 

 relation as the extremities of one or more octaves in music. 

 Thus, in the nitrogen group, between nitrogen and phos- 

 phorus there are 7 elements ; between phosphorus and 

 arsenic 14; between arsenic and antimony, 14; and lastly 

 between antimony and bismuth, 14 also" (Chem. News, 

 Aug. 1 8, 1865; Periodic Law, p. 14). 



This peculiar relationship Newlands proposed to term 

 provisionally the LAW OF OCTAVES. It was described at a 

 meeting of the Chemical Society on March i, 1866, and 

 was criticised "on the score of its having been assumed 

 that no elements remain to be discovered." One Fellow, 

 whose misdirected wit has provided a perennial warning to 

 rash critics, " humorously inquired of Mr. Newlands whether 

 he had ever examined the elements according to the order 

 of their initial letters ? " Newlands replied that " he had 

 tried several other schemes " and had found that " no rela- 

 tion could be worked out of the atomic weights under any 

 other system than that of Cannizzaro " (Periodic Law, p. 19) ; 

 but the paper was rejected and failed to secure attention 

 until similar relationships were put forward five or six years 

 later by Mendeleeff and by Lothar Meyer. 



