ElvISHA MITCHELL SCIENTIFIC SOCIETY. 33 



When it comes to studyino- the compounds they are 

 studied connectedly. Thus the hydrides of all the ele- 

 ments, are examined, g-iving- their relation to hydrog-en; 

 then the oxides and the influence of the negfative and posi- 

 tive nature of the elements upon their relation to oxygen 

 and hydrog-en. Under the head of each acid (for the acid 

 larg-ely determines the g-eneral characteristics of the 

 salt) the various salts are discussed. This gives a bet- 

 ter understanding of the characteristics, saves repetition 

 and tends to fix in the memory the compounds or classes. 

 And so too the constant taking- up of the elements in their 

 g-roups and series fixes them in the mind. 



I cannot gfive the system in detail. Study the periodic 

 system and Meyer's lecture carefully and then laying- 

 aside prejudices and traditions g-o boldly to work. What 

 I have stated about the advantag-es of the system may 

 seem overdrawn. The statements are based upon an ex- 

 perience of three years and no one has the rig-ht to g-ain- 

 say them until he has faithfully tried the system. 



