1^15.] connected with the Atomic Theory. 187 



salts which I have published, he will have been struck with some 

 other anomalies of a similar nature to those belonging to the salts of 

 lead ; but 1 forbear touching upon them at present, till we are in 

 possession of more perfect analyses than have been hitherto pub- 

 lished. 



2. Certain salts have been analyzed, the composition of which, 

 wlien stated in symbols, presents us with the anomaly of 1^ atoms 

 of one substance combined with one atom of another. Thus sub- 

 sulphate of iron is composed thus, 1 (S O^) + 1 i (F O®) ; or it 

 contains one integrant particle of sulphuric acid and 1-i- integrant 

 particle of black oxide of iron. As such a composition is obviously 

 impossible, it is clear that in such cases a certain number of inte- 

 grant particles of sulphuric acid must be combined with a certain 

 number of integrant particles of oxide of iron. If we multiply by 

 two. the anomaly will disappear. We shall then have 2 (S O^) + 

 3 (F O') ; that is to say, the salt is a compound of two integrant 

 particles of sulphuric acid and three integrant particles of black 

 oxide of iron. Such combinations do not present any thing incom- 

 patible with the atomic theory, which admits of such combinations ; 

 but they constitute exceptions to one of the general laws which 

 Berzelius has deduced from his numerous analyses. The law is, 

 that in all inorganic compounds one of the constituents always 

 enters in the state of a single atom. In the subsulphate of iron 

 there is no single atom, either simple or compound. It consists of 

 12 atoms of oxygen, three of iron, and two of sulphur; or of two 

 integrant particles of sulphuric acid and three integrant particles of 

 black oxide of iron. The composition of the subsulphate of copper 

 may be explained in the same -way. Its symbol is I (S O^) + 

 H (C 0-), or one integrant particle of sulphuric acid combined 

 with 1 J- integrant particle of black oxide of copper. If we mul- 

 tiply by two we obtain 2 (S O') + 3 (C 0-), which 1 conceive to 

 be the real constitution of the salt ; namely, a compound of two 

 integrant particles of sulphuric acid with three integrant particles of 

 black oxide of copper. The subarseniate of lead admits of the 

 same explanation. Its symbol is I (As O') + l,}(PO*), or one 

 integrant particle of arsenic acid combined with l^y integrant par- 

 ticle of yellow oxide of lead. When we multiply by two we obtain 

 2 (As O') 4- .'i (I* 0-) ; that is, two integrant particles of arsenic 

 acid united with three integrant particles of yellow oxide of lead. 



Various other similar examples might be adduced ; but they are 

 all explicable in the same way. 'J'hey appear to me to constitute so 

 many exceptions to BerzeLius's law above-mentioned, and to show 

 that it doe« not hold so universally as he had supposcvl. 



3. I'rolessor lier/clius has just favoured the chemical world with 

 an analysis of a cousiderablc immlier of the vegetable acids, and 

 somfe other vegetable substances. That thcie exi)erimeuts have been 

 conducted with the greatest care is evident from the details into 

 which Berzelius has entered ; nor have I the least doubt, from the 

 nncominon precision which <haracteri/cs wlialcver is done by this 



