S>58 
Mr Stodart and Mr Faraday 
way chalybeate solutions, containing small portions of protoxide 
of iron, may be readily obtained. 
The cause of the increased action of acids on this and similar 
alloys, is, as the President of this Society suggested to us, pro- 
bably electrical. It may be considered as occasioned by the al- 
loying metal existing in such a state in the mass, that its parti- 
cles form voltaic combinations with the particles of steel, either 
directly, or by producing a definite alloy, which is dilfused 
through the rest of the steel ; in which case, the whole mass 
would be a series of such voltaic combinations ; or it may be oc- 
casioned by the liberation, on the first action of the acid, of par- 
ticles which, if not pure platina, contain, as has been shewn, a 
very large proportion of that metal, and which, being in close 
contact with the rest of the mass, form voltaic combinations with 
it in a very active state : or, in the third place, it may result 
from the iron being mechanically divided by the platina, so that 
its particles are more readily attacked by the acid, analogous ta 
the case of proto-sulphuret of iron. 
Although we have not been able to prove by such experi- 
ments, as may be considered strictly decisive, to which of these 
causes the action is owing, or how much is due to any of thern^ 
yet we do not hesitate to consider the second as almost entirely, 
if not quite, the one that is active. The reasons which induce 
us to suppose this to be the true cause of the action, rather than 
any peculiar and previous arrangement of the particles of steel 
and platina, or than the state of division of the steel, are, that 
the two metals combine in every proportion we have tried, and 
do not, in 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 in- 
finitely minute voltaic combinations of steel and platina, but ex- 
actly as steel alone would do ; that the mass does not render 
platina wire more negative than steel, as it probably in the third 
case would do ; that it does not rust more rapidly in a damp at- 
mosphere ; and that when placed in saline solutions, as muriate 
of soda, &c., no action takes place between them. In such 
cases it acts just like steel ; and no agent that we have as yet 
