348 Transactions.—Chemistry. 
with it in pure hydrochloric acid, mercurous chloride forming. 
5. That platinum can be substituted for graphite’ in the above ex- 
periments, with the same general results. 
I further find that charcoal does not, even when freshly prepared, 
notably liberate iodine ; but it can be made to do so by digesting it with an 
acid, the effect of which is perhaps due to its removing all alkaline matters 
therefrom, and thus enabling the charcoal to retain the oxidizing agent 
necessary for effecting the liberation in view. 
Silver, also, liberates iodine from the solution of it I have named here, 
and gold even appears to do this, but to a much less extent. 
Nitric acid has the same effect upon either graphite or platinum (in 
relation to iodine) as exposure to air has, and prolonged washing of these 
metals afterwards does not in any way interfere with this effect, showing, 
no doubt, that this acid has been absorbed by these metals and is retained 
very obstinately. 
The graphite I used was of course purified both from iron and mangan- 
ese before being worked with. 
In reference to the chemical action of substances upon which oxygen 
has been in some way condensed, I may perhaps be allowed to state further 
that when graphite, which has been exposed to the air, is voltaically con- 
nected in sea water with graphite just recently ignited, electric currents are 
generated ; graphite, which has been desulphurised, also generates electric 
currents when connected in this manner with any negative conducting 
sulphide in a solution of an alkaline sulphuret. By the use of currents 
generated in this manner I have even electrolyted copper from its sulphate. 
I forbear making any specific deductions from the results above related 
until I can supplement them in such a way as will enable me to discrimin- 
ate with greater surety than I at present can, the exact nature of the 
absorptive process by which graphite and platinum become chemically active 
in the way these results indicate. 
Ant. L.—Analyses of a few of the Fire-clays of the Province of Auckland. 
Ponp. 
[Read before the Auckland Institute, 11th October, 1875.] 
Ty introducing the subject of my paper this evening I am painfully aware 
how imperfectly I have treated it in reference to clays from different dis- 
tricts which have not even been mentioned. Many excellent samples, I have 
no doubt, have yet to be discovered, while some which have been spoken 
of as excellent refractory clays, I have been unable to obtain for comparative 
