3g4 ox TIIE OXIDES OI' IROTf. 



oxide, lie says, constitutes thefirst; and the Greek prepositioti 

 Trr^a prefixed constitutes the second. Had Mr, Hasscrifratz 

 taken the trouble to consult my Avork, volume ), p. 140, 

 answered. (3d. edition) he would have seen, t\mt peroxide was formed 



by joining the Latin preposition per to the word oxide ; and 

 that, according to a very common use of that prepositiort 

 in Composition, the word peroxide means a metal thoroughly- 

 oxidized, or saturated vrith oxigen. He thert proposes to 

 substitute for the words protoxide and peroxide the words 

 micro fsoxideund tnegaloxidc, which he says are much more 

 precise. I belies, c it to be unnecessary to make any obser- 

 vations on this proposed substitution. Irt what respect 

 these words are more precise than mine, or indeed so pre- 

 cise, I am at a loss to conceive. They signify literally /2Y//e 

 oxide and great oxide, phrases which lead us rather to 

 attend to the bulk of the substances, than to the propor- 

 tion bf oxigen which they contain. But even supposing 

 them equally or even more precise, still they could not be 

 substituted for mine; because we require a method of 

 naming- all- the oxides of a metal, even when they exceed 

 two. My method supplies such a nomenclature; but Mr. 

 Hassenfratz's method, even if we were to introduce also 

 his words oxidule and oxidi^q^ie, supplies no stich nomen- 

 clature. The same insurmountable objection applies to the 

 oxidule of Fourcroy and Hauy. Besides, Mr. Hasscnfratz 

 frjrgets^ that the term oxidule, though it does well enough in 

 French, may not be suited to other languages. For in- 

 stance it would neither be introduced into English nor 

 Gi!nnan, without doing violence to the genius of both 

 languages. 



VI. The preceding experiments were made about a year 

 ago ; indeed immediately after perusing Mr. Hassenfratz's 

 dissertation. I publish them at present, to put the che- 

 mical public on their guard respecting the inaccurate state- 

 ment of the composition of oxides of iron, which I have 

 introduced into my Si/.sfem of Chemistri/. I inserted the 

 result of theni in the appendix to the 4th edition of that 

 work; but thought it requisite likewise to publish the de- 

 tails, that those who are in possession of preceding editions 

 may be aware of th* inaccuracy and correct it. 



INDEX 



