MANUFACTURE of CEMENT from TARANAKI IRONSAND.

Patea Mail, 12 February 1881, Page 4

MANUFACTURE of CEMENT from TARANAKI IRONSAND.

The Post gives the following further particulars of Dr Monro’s offer to supply cement to the Wellington City Council : In our issue of the 4th February, we mentioned that Dr Munro, of Wellington had written to the City Council stating that he had succeeded in making cement at a cost little exceeding the freight of the imported article. The doctor has now applied for a patent for his invention, and in the meantime has secured protection for a period of six months. The materials arc iron sand and volcanic matter chemicalJj' treated, and are to be obtained in Taranaki in unlimited quantities. Dr Munro, who is a gentleman of very considerable scientific attainments, some months ago had his attention drawn to the fact that there existed in Taranaki in immense quantities the two principal ingredients for the manufacture of cement, and set about experimenting with them, and he has now some specimen blocks which he is of opinion cannot be excelled in regard to durability, and certainly not equalled in point of cheapness. He has had the opinion of various contractors and others acquainted with cements, and these assert that the specimens made by him arc superior to anything they have seen. It is calculated the blocks will bear a pressure of fully 4001bs to the square inch, and that about 10s per ton would cover all expellees. If this is so, then the advantages of Dr Munro’s invention can scarcely be over-estimated, as Corporations and Harbor Boards would be able to save many thousands of pounds annually now spent in Portland cement. With everything just to hand for manufacturing this cement by the hundreds of thousands of tons, what a vast saving might be effected in the construction ot the New Plymouth breakwater—always providing it can bo shown beyond doubt that the cement so manufactured would be suitable for the purpose ; and the inventor says he can demonstrate that to an absolute certainty —that in fact it is similar to the cement used by Smeaton in the building of the Eddystone lighthouse, and to the material used by the Romans for the foundation of their bridges before the Christian era, the remains of which arc yet in existence. He further states that by pressure the blocks of this cement will adhere to each other, and in the process of time form one solid mass. Dr Munro expressed surprise that with all this valuable material under their very feet the people of New Plymouth should have remained so long in ignorance of its immense value. Before trying the Taranaki ironsand, Dr Munro experimented with the Wanganui and other sands, but found them to be deficient in iron, but the ironsand on the New Plymouth beach, containing 50 per cent, of iron, forms by a mixture of volcanic matter, treated by a

simple chemical process, a cement which cannot be surpassed. We have been invited to inspect the cement in various stages of completion. One block which had been placed in water last night had set ; another which had been in water 24 hours had become perfectly hard, and a third block, which had been some days in water, had the appearance of a block of solid lava. The sand used is fine, and the blocks are consequently very close ; but we are informed that if still greater cheapness were desired for paving and other purposes, gravel might be mixed with the cement and an excellent concrete made thereby. There is about 25 per cent, of iron in the material used, so that the blocks are very heavy. No doubt the invention will be brought prominently under the notice of the public, as Dr Munro intends communicating with the Taranaki breakwater authorities and all the New Zealand corporations, offering them the right to use his invention upon the payment of a small royalty. In view of the alleged cheapness of the material and the durability of the cement, the subject is well worth the attention of practical men.