Di*. E. J. Mills on Elective Attraction. 525 



dicated by the followiug equations, the bracketed portions indi- 

 cating potential (probably not actual) substances : — 



a = 6-0 6MN03 + 2POCP = 6MCl + P2 0-^ + 3[N2 05], 



a = l-5 6MN03 + 8POCF=6MCl + 4P2 0H-6[NOCl3]. 



By taking the first equation a times and the second b times, 

 the elective coefficients may be reconciled with the whole num- 

 bers required by common chemical equations. 



The value of M in the silver group, when a = 6*0, would 

 be 125-5, and for a = 1-5 an analogue of lithium would have 

 the symbolic value 4 nearly. 



(7) That the intensity of elective attraction is proportional 

 to symbolic value, is written explicitly upon every page of the 

 history of chemistry. I shall merely draw attention to a few 

 out of hundreds of examples that might be adduced to cor- 

 roborate the correctness of the law, and the fact that chemists 

 have long unconsciously been guided by its results. 



When argentic nitrate is added to a dilute aqueous solution 

 of potassic iodide, bromide, and chloride (these salts having 

 been mixed in any proportion), argentic iodide, bromide, and 

 chloride are successively precipitated, that is, in the order of 

 their symbolic values. Argentic chloride may be wholly con- 

 verted into bromide by digestion with aqueous potassic bromide ; 

 and argentic bromide is completely transformable into iodide by 

 aqueous potassic iodide. These comparisons are extremely fair 

 of their kind. The comparison of hot free chlorine with iodine 

 weakened by combination with silver is of course not a fair com- 

 parison. 



In the formation of salts, baryta has the preference over 

 strontia, and strontia over lime. 



In the fractional separation of the volatile members of the 

 fatty series C« Hs^i O2 by Liebig^s process, the law is strictly ob- 

 served, excepting in the case where n = 2, which is an intelligible 

 anomaly. Heintz's method of separating the non- volatile mem- 

 bers of the same series by means of magnesia exhibits the same 

 order. 



In a mixture of the hydrocarbons C„ H2„_6, benzol is the last 

 to be chlorinated or nitrated. 



Warington has shown the superiority of ferric over aluminic 

 oxide as an absorber of alkalies in soils. 



In cases of jaundice, taurocholic acid is destroyed in the sys- 

 tem before glycocholic acid. 



It was the aim of the distinguished Bergman to unite all che- 

 mical substances in a series according to the principle of elective 

 attraction. A great part of his life was passed in experimenting 

 qualitatively with a view to that purpose ) and he left on record 



