850 Transactions.—Chemistry. 
population and the consequent high rate of carriage, and this induced me 
to turn my attention to samples of clay nearer Auckland. Several of these 
I received from Mahurangi, but only one was a refractory clay. Some time 
since I thought the peculiar deposits at Fort Britomart might be worth a 
trial, and having obtained several samples, and finding them very refrac- 
tory, I carefully examined them, and was surprised to find how excellent 
a clay had been overlooked. Any observer, at the time of the cutting 
through Fort Britomart being made, would have seen some peculiarly 
marked bands of earth under the superficial soil, the uppermost being a 
bright red band about two feet in thickness, composed of sandy particles 
with a large per centage of iron oxide, and immediately beneath it a dark 
brown band of earth for a depth of about three or four feet, and superim- 
posed upon a layer of white clay, having a depth in some places of five or 
six feet. These two distinct bands consist of very fair samples of refractory 
clays, the latter being by far the best, and very little, if at all, inferior for 
the purpose of fire-brick making, to the Waikato and Bay of Islands clays. 
The difference in the constituents of these bands is remarkable, seeing how 
they are situated. The insoluble matter in all the samples analysed is a 
very large per centage—in no instance less than 90 per cent. The Brito- 
mart samples contain a small quantity of pyrites ; this has, however, been 
- included in the oxides of iron, and the total is not a large per centage. It 
may be worthy of remark that during the removal of the earth from the 
corner of Albert and Custom-house Streets by the Harbour Board, I found 
the bands identical with those at Britomart, and feel confident that they 
were a continuation of the same layers which dip slightly to the westward. 
At the time of this removal several hundred tons of this valuable clay 
must have been thrown into the Harbour. I think the admixture of the 
two clays might be judiciously carried out if any practical use was going 
to be made of them, but in what quantities, would be better seen by 
experimental use. The last clay to be mentioned is from Mahutangi, and 
is a fair sample, entirely free from lime and magnesia, the alkalies being 
larger in proportion than any of the others. This sample is the only one 
which contains chlorine, and this may be accounted for from its being a 
portion of the cliff facing the sea. I may remark that I had purposely 
allowed the samples to become very dry before examination, and had 
chosen the Waikato and Bay samples as free from bituminous veins as 
possible. 
In bringing this paper before the Institute, I have not the mere {easi- 
bility of fire-brick making in view ; but when we consider the valuable beds 
of clay we possess, and in many instances the easy access by water, it will 
be seen what facilities we have for the manufacture of porcelain, earthen- 
