MANUFACTURE OF CEMENT FROM TARANAKI IRON SAND.

Evening Post, Volume XXI, Issue 29, 5 February 1881, Page 2

MANUFACTURE OF CEMENT FROM TARANAKI IRON SAND.

I—+1 — + In our issue of Friday last we mentioned that Dr. Munro, of this city, had written to the City Council stating that he had suooeded in making cement at a cost litulo 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 are ironsand and volcanic matter chemically treated, and arc to be obtained in Taranaki in unlimited quantities. _ Dr. Munro, who ia a gentleman of very considerable scientific attainments, some months ago had his attention drawn to the fact that thero existed in Taranaki in immense quantities the two principal ingredients for the manufacture of o >ment, and set about experimenting with them, and he has now some specimen blocks which he is of opinion cannot bo 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 tho specimens made by him are superior to anything they have seen. It is calculated tho blocks will bear a pressure of fully 4001bs. to the square inch, and that about 10s per ton would about cover all expenses. If this is so, then the advantages of Dr. Munro's invention can scarcely be over-estimated, as Corporations and Harbour Boards would be able to save many thousands of ponnds 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 of the New Plymouth breakwater — alwayß providing it can be shown beyond doubt that the cement so manufactured would be suitable for the purpose ; and tho inventor says he can demonstrate that to an absolute certainty — that in fact it is similar to the cement used by Smeaton in tho building of the Eddystono lighthouse, and to the material used by the Romans for the foundation of their bridges before the Christian era, the remains of which are yet in existence. He further asserts that by pressure the blocks of this cement will adhere to each other, and in the process of time form one solid mass. He 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 valuo. Before trying tho Taranaki ironsand Dr Munro experimented with tho Wanganui and other Bands, bnt found them to be deficient in iron, but the ironsand on the New Plymouth beach, containing 50 por cent of iron, forms by he 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 lost 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 Band used is fine, and the block are consequently very close ; bnt wo 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 mado thereby. There is about 25 per cent, of iron in the material used, so that the blocks are very heavy. No donbt the invention will shortly 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.

Turning the Tables.— Looking through i "Bradshaw."