f)2 CLASSIFICATION OF CHEMICAL AGENTS. 



e«Harstate of certain states of oxidation only. Thus if sulphate of iron 

 * be exposed in solution to the action of the atmosphere, the 

 ' iron become farther oxidated, insoluble in the acid, and 



preci[)itates. Hence arises an extremely curious fact, 

 namely, that a metallic oxide may precipitate u ditlerent 

 oxide of the siune metal. And ou the other hand it some- 

 times happens, that an oxide will ordy combine with an acid 

 uhen tliis latter contains a certain proportion of oxigen : this 

 occurs in the mixture of the oximuriatic acid with the al- 

 kalis: a muriate and hyperoki muriate of the alkali are 

 formed, 

 or disposing af. Or if a combination of this kind should take place, an 

 eneri^etic dispoising afTuiity is exerted, so that oxigen is at- 

 tracted, and the appropriate states of oxidation come to be 

 fultilied ; as is exemplified in the sulphurets, sulphites, 

 phosph:.rets &c. 

 New names. With rej^rdto the names, which I have suggested tO' ex- 



press the articles of the fourth and fifth classes; I am by qo 

 means Convinced of the neces:^ity fo» their ?»doptioh, and 

 less btill am 1 satisfied with the denominations, which I have 

 ventured to offer, especially with that of aoxuretj' or, tjs it 

 might be rendered, anoxuiet. The term oxuret was chosen 

 Irom its conformity with the general plan of chemical no- 

 menclature, as in the examples, sulphuret, phosphurel, hi- 

 drognret, &c. ; the privative particle a is prefixed to tlirs 

 term, to denote the snbstances of the fourth clii»s. 

 Amngement The plan, which arranges chemical substances according 

 as elementary ^* ^^^y '"^^^ elementary, or compound, is, from the daily ad- 

 orconipund vancement of chemical !Hciieore,p^<'pe#Uatly V<ibjt?<'t to 

 lual change!^ ' change; for that substance, which vVecOnsider'tod-iy as sim- 

 ple, may very shortly be discovered to be compounded. 

 The classification of substances, fonhded on relations in their 

 chemical properties, since it is not liable to change from dis- 

 coveries in' the analysis of bodies, will be more permanent, 

 >\(Wjnfapes of I iniHgine, that the urrangement, tvhich I have suggested, 

 the uuaior'i ^yji| ]^g allowed to possess, independantlv of the advantages 

 of the latter planV certain others, which are peciiliar'to it- 

 self, and by no means unimportant. Tlie assistimce which 

 it affords to tlie memory, and the extensive knovvkdge it 



toijvtys 



