37 JOURNAIy OF THE 



in horizontal series. They differ widely in many impor- 

 tant points. Some teachers make use of one, some of the 

 other. The Germans and many teachers in England and 

 America use Meyer's horizontal table. Many other tables 

 have been proposed but they differ widely from those of 

 the two g-reat discoverers of the Periodic System and are 

 generally intended to present and advocate some scheme 

 as to the Genesis of the Elements or some other wild and 

 questionable fancy. 



I may be pardoned a brief reference to the table worked 

 out by myself and suggested as an aid to teachers. It 

 does not depart ver}^ far from the Mendeleeff horizontal 

 table, but my own experience has proved it to be more 

 easily taught and more quickly learned and hence very 

 valuable for the teacher. It certainly brings out some 

 facts which no other table presents, and when our know- 

 ledge is fuller it may aid in solving some of the puzzles 

 now connected with the system. 



It must be said that none of the systems are satis- 

 factory, all are imperfect and incomplete and must remain 

 so until our knowledge of the science is itself complete. 

 Recent growth in the science has shown the insufficiency 

 of the older arrangements. The discover}^ of argon and 

 helium (and shall we add asterium?), the repeated de- 

 termination of the atomic weights of iodine and tellurium 

 and of the nearly twin elements cobalt and nickel show- 

 ing them to be out of place in Mendeleeff and Meyer tables, 

 have proved surprising reverses to the system after the 

 brilliant successes of its earlier history. In the first table 

 the existence of new elements had been predicted with an 

 exact statement of their properties. These predictions 

 had been marvellously fulfilled in the discovery of scan- 

 dium, gallium and germanium. It was to be expected 

 that future discoveries would only strengthen that which 

 was already so strangely confirmed. But these new ele- 

 ments, argon and helium, were not predicted and refuse to 

 be fitted into the system, as at present constructed, and are 



