1 823] the Alloys of Steel 206 



acted, but not with much power; with 50 per cent the action 



was not more than with steel alone ; and an alloy of 90 platina 

 with °0 steel was not affected by the acid. a.*-* 



The action of other acids on these alloys » similar to that of 

 ,iilnhuriTacid and is such as would be anticipated : dilute 

 nffiic add .phosphoric acid, and even oxalic acid acted on 

 Se plaSna alio? *«* the liberation of more gas ^n from zinc ; 

 and tartaric acid and acetic acid rapidly dissolved it, In this 

 way chalybeate solutions, containing small portions of protoxide 

 of iron may be readily obtained. 



The causl of the increased action of acids on this and similar 

 allovs is as the President of this Society suggested to us, proba- 

 ta iectrical. It may be considered as occasioned b> .the 

 alloying metal existing in such a state in the mass, that its par 

 S form voltaic combinations with the particles of steel, either 

 directly or by producing a definite alloy, which is diffused 

 through the res? of the Iteel ; in which case the whole mass 

 would be a series of such voltaic combinations ; or it may be 

 occasioned by the liberation, on the first action of the acid, of 

 "a tTcks wh ich, if not pure platina, ^T^^eZmZ^ 

 a very large proportion of that metal, and which, being in close 

 contact wlh P the rest of the mass, form voltaic combination. 

 w° hTt in a very active state ; or, in the third p ace t may result 

 from the iron being mechanically divided by the platina, so that 

 its particles are more readily attacked by the add, analogous to 



as may be considered strictly decisive, to which of these causes 

 Se action is owing, or how much is due to any of them, yet we 

 do not hesitate to "consider the second as almost entirely, if not 

 Site the one that is active. The reasons which induce us to 

 iCose this to be the true cause of the action, rather than any 

 SSar and previous arrangement of the particles of steel and 

 Kna or than the state of division of the steel, are that the 

 [wo metals combine in every proportion we have tried, and do 

 no? hi any case, exhibit evidences of a Separation between 

 them like those, for instance, which steel and silver exhibit; 

 that when, instead of an acid, weaker agents are used the alloy 

 does not seem to act with them as if it was a series of infinitely 

 minute voTtac combinations of steel and platina but exactly as 

 Seel alone would do ; that the mass does not render platina wire 

 more negative "than steel, as it probably in the third case would 

 T thafit does not rust more rapidly in a damp atmosphere ; 

 and that when placed in saline solutions, as muriate of soda, 8vc 

 there it no action takes place between them. In such cases it 

 icts iust like steel ; and no agent that we have as yet tried, has 

 SXed voltaic action that was not first able to set a portion of 

 the platina free by dissolving out the iron 



Other interesting phenomena exhibited by the action ot acid 



