examination. For instance, Raglan, Coromandel, Wangarei, the Manukau, and many other parts of the country have sent clays competing for the foremost place for the purpose of fire-brick making, one notably from Taranaki, which was supposed to be very valuable for this purpose, proved on examination to be a silicate of magnesia, and formed a most delightful glazed surface at a high red heat, while at a white heat it was in a perfect state of fusion. But undoubtedly the Province possesses some excellent deposits of refractory clays; and some of these I now place before you.

As the diagram will show, I have, for comparison, placed the celebrated Stourbridge clay first, as this has a world-wide reputation. Of the New Zealand, or at all events Auckland clays, I think the Waikato fire-clay has been the most noticed, and it has certainly deserved to be held in high estimation, for it is an excellent clay, but it must, I think, give place to the sample from the Miranda or Wharekawa coal seam. This latter, as will be seen, contains much less iron than the Waikato, and an entire absence of lime, which, in the other analyses, amounts to only a small per centage. The clay next in value is the Bay of Islands, but this, with a higher per centage of lime and iron, would not permit of so white a biscuit being made from it. One thing noticeable in the Waikato and Bay of Islands clays is the large amount of bituminous veins running through them, though entirely absent in the Miranda sample. I do not consider this prejudicial, as it would require less fire to burn the brick, though on the other hand the contraction would be greater and the brick more porous. I may say respecting the Miranda clay that I am indebted to Mr. Tunny for this analysis, but that a sample analysed some time since for the Wharekawa Coal Co. contained 11 per cent. of bituminous matter, which was distributed finely throughout, as if permeated by it. The Waikato and Bay of Islands clays have been most used in Auckland for manufacturing purposes, the former being largely used by the gas works, foundaries, and glass works of this city, and I believe the furnaces for the smelting of iron sand at Taranaki and the Manakau Heads have been made of the same material. With reference to its use for melting-pots at the glass works, the manager complained bitterly of the manner in which it had been collected at the mines and mixed with worthless material, by which it was greatly deteriorated, and it was found necessary in consequence to mix some imported Sydney clay with it. One peculiarity of the Waikato clay is its extreme friability after exposure, which is taken advantage of by the manufacturers before alluded to, and though at first a large sum was paid for the grinding of it, now it is simply left to the action of the weather for a few weeks, and is then in a state of fine division. The great drawback to the increased use of fire-bricks is the distance of the known deposits from the centre of

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 refractory, 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 superimposed 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 Britomart 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 feasibility 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, earthenware,