266 Mr. G. C. Foster on Chemical Nomenclature, 



The original meaning of the term base is perhaps even less 

 clear than that of the word acid. According to Kopp* it was in- 

 troduced by French authors, and occurs frequently from about 

 the year 1730. With regard to its earliest meaning, he says, 

 " The following passage from Rouelle's ( Memoir on the Neutral 

 Salts 3 (1754) may give some idea of the sense connected with 

 the use of this word : — '*Pai etendu le nombre des sels autant 

 qu'ii etait possible, en definissant generiquement le sel neutre, 

 un sel forme par Punion d'un acide avec une substance quel- 

 conque, qui lui sert de base et lui donne une forme concrete ou 

 solide/ (Stahl employs a periphrasis similar to the above to 

 express what we now call a base ; in his Specimen Becherianum 

 [1702], he denotes the substance which is contained in chloride 

 of sodium in combination with an acid as materia ilia, quce salt 

 corpus prmbet.) " The word " base " occurs very frequently in 

 the writings of Lavoisier, but with him, as in the above quota- 

 tion from Rouelle, it appears to have retained very much of its 

 etymological meaning of foundation, and not in any degree to 

 suggest the possession of properties opposed to those of acids. 

 The following passage may serve to illustrate his use of the 

 term : — " II est infiniment rare d'y trouver [in the vegetable 

 kingdom] un acide simple, c'est-a-dire qui ne soit compose que 

 d'une seule base acidifiable. Tous les acides de ce regne ont 

 pour base Phydrogene et le carbone, quelquefois Phydrogene, 

 le carbone et le phosphore, le tout combine avec une proportion 

 plus ou moins considerable d'oxygene. Le regne vegetal a 

 egalement des oxides qui sont formes des memes bases doubles 

 et triples, mais moins oxygenees " (Traite elementaire, vol. i. pp. 

 124, 125, edit. 1789). The modern word equivalent to ' base 3 in 

 this passage would evidently be ( radical/ as is clearly shown by 

 the one which follows : — " II faut done distinguer dans tout 

 acide, la base acidifiable a laquelle M. de Morveau a donne le 

 nom de radical, et le principe acidifiant, e'est-a-dire, Poxigene " 

 (Ibid. p. 69). 



The limitation of the term base to salifiable bases only, seems 

 to be of comparatively recent introduction, and is probably due 

 to Berzelius ; but even with this limitation it has never been 

 confined exclusively to bodies of any one class. Ever since the 

 expression salifiable base came into use, it is probable that almost 

 all chemists have been agreed in considering it as applicable to sub- 

 stances as variously constituted as those represented by the for- 

 mulae KHO, K 2 0, PbO, NH 3 . In the following passage, how- 

 ever, Professor Williamson seems to imply that Gerhardt confined 

 the word base to basic hydrates only : — " In fact he [Gerhardt] 

 systematically applied the term acid to hydrogen-salts, giving 

 * Geschichte der Chemie, vol. iii. p. 69. 



