242 THE DISCOVERY OF NEW ELEMENTS. 



The discovery of germanium, predicted under tlie name of ekasilicon 

 by Mendelejeff, recalls the discovery, by Galle, of the planet Neptune, 

 whose existence had been shown by the calculations of Adams and 

 Leverrier. This discovery was not due to the concurrence of favorable 

 circumstances or to a happy accident; it resulted from researches 

 undertaken because of theoretical previsions, and the agreement be- 

 tween the predicted and real properties was snch that Mendelejeff con- 

 siders the discovery of germanium the principal justification of the law 

 ot periodicity.' 



On one point only has germanium completely deceived expectations; 

 that is, with regard to its formations in nature. It might have been 

 expected that it would rather have been found as an oxide in the rare 

 minerals of the North, in company with titanium and zirconium, than 

 as a sulphide in company with analogous combinations of arsenic and 

 antimony in the vein rock of avgentitcrous minerals. This circum- 

 stance, together with the comparative rarity of its mineral, argyrodite, 

 has contributed not a little to retard the elucidation of its true char- 

 acter; I am myself Inclined to consider it as eka-antimonj', while 

 Mendelejeff, after my first incomplete communications to him, sup- 

 posed it to be ekacadmium. At about the same time M. von Eichter 

 expressed his conviction that germanium could be nothing else than 

 the long-expected ekasilicon; an opinion which he justified by the 

 agreement of their atomic weights. 



Although gallium and germanium keep peace with each other, show- 

 ing that science is above all national quarrels and political agitations, 

 the denomination of germanium which I have given to the new element 

 has aroused some criticism,^ and it has been said that I ought to 

 renounce that name, which has too marked a territorial flavor. I need 

 not say that this demand seems to me quite unjustifiable, for I have 

 only followed the example given by the denominations gallium and 

 scandium, concerning which the same criticism could be made. 



The success of the bold speculations of Mendelejeff allows us to affirm 

 that the elaboration of the periodic system is a great forward step for 

 science. In the course of only fifteen years all the predictions of the 

 Eussian chemist have been confirmed, new elements have been placed 

 in the gaps which he left in his table, and there is reason to hope that 

 it will be the same for those which still remain in the natural system. 



Still, the last two elements discovered — argon and helium — seem to 

 have no relation with the periodic system. After Lord Eayleigh,^ in 

 1892, had proved that nitrogen obtained from chemical combinations 

 was about one-half per cent lighter than that obtained from the atmos- 

 phere, a determination that was again verified in 1894,^ Lord Eayleigh 



'D. Mendelejeff, Principes de chimie; St. Petersburg; 1891 (p. 692). 

 ^Moniteur Scieutifique, June 1886 and March 1887. 

 ^Lord Eayleigh, Chem. Xews, 69. 

 ^Lord Rayleigh, Proc. Roy. Soc, 55. 



