65

H.—22

No. 66. Evidence of Mr. W. A. Ewing before Mr. Commissioner Burns, at Dunedin, 26th May, 1880. My name is William Anderson JSwing. I am a builder in Dunedin. I have applied for a patent for the manufacture of cement from stone found in the neighbourhood of Dunedin, which I believe is equal in quality to any cement that is imported. It would be of great service to the starting of this industry if the Commission could recommend to the Government the offering of a bonus towards this manufacture ; and I think I could successfully start this industry if the Government would give me an order for, say, a hundred tons, to be delivered in such quantities as may be agreed upon, —the quality to be subjected to any fair inspector appointed by Government —at the then market price of the best quality of Portland cement delivered in Dunedin. W. A. Ewing.

No. 67. Mr. Chables D. Ibyine to the Royal Commission on Local Industries. Gentlemen, — Wellington, 31st May, 1880. The large quantity of cement annually imported into this country, the growing use of the article in the formation of artificial flagging, curb and channel stones for streets, buildings, breakwaters, and pipes and sewers for drainage works, taken together with the general scarceness of stone fit for these purposes, indicate the value of a thorough investigation into the question of the desirability of affording Government encouragement, by bonus or otherwise, to the erection in the colony itself of one or more factories for the proper manufacture of this article. Wherever silica, carbonate of lime, and alumina are met with in a moderately easily-convertible form, Portland cement can be made. The manufacture differs slightly according to the varieties met with in the constituents named, but in the main consists in—Ist, the thorough mechanical combination of the raw materials; 2nd, their calcination ; 3rd, their reduction to fine—almost impalpable —powder by grinding. On the Thames, white chalk is used in combination with Medway mud. In many works on the Medway grey chalk is substituted for white, and Gault clay is used instead of Medway mud. At Harwich and Stockton a local blue .clay is used in combination with chalk imported from the Thames. In the North of France a natural cement-earth is found, which often contains the exact proportions of lime, silica, and alumina for the production of a high-class cement. In Somersetshire and other parts of England the blue-lias formation supplies the requisite ingredients. In Derbyshire, limestone, in combination with tufa found in the same locality, is made available. In Buckinghamshire there is a natural deposit of cement-earth immediately underneath the surface, and with it is intermingled a considerable quantity of nodular limestone. At Aberystwith, in North Wales, a nodular limestone is found which contains all the ingredients, existing in the best proportions. In India a cement is made from lime produced from sea-shells used in combination with river-mud; and at Rio de Janeiro similar raw materials are used for the same purpose. In many parts of New Zealand nodular limestones with marly and blue clays are found, in juxtaposition, which afford all the raw materials necessary for the production of the very highest class of Portland cement; and lam of opinion that, were Government to erect a proper manufactory, or assist private enterprise to do so, it would very soon be demonstrated that the best class of Portland cement could be manufactured in the colony at a cost considerably under what the article can be imported for. At present the Harbour Board are contemplating the erection of a breakwater at New Plymouth roadstead, to be built of cement concrete at a cost of £200,000; and, as the price of the cement to be used in the work comes to about one-half of the cost of the whole finished work, the sum of £100,000, were the cement manufactured in the locality, would be expended in wages instead of being paid away for the imported article; and, provided that an equally good cement can be manufactured on the ground at the same price as the imported article, no loss to the colony would ensue. Within a few miles of New Plymouth, nodular limestone and blue clays are found which are capable of yielding a Portland cement equal to the best imported article. Dr. Hector was the first to point out the existence of this peculiar formation and the use that the materials may be turned to; and I myself made several experiments of a tentative nature with this nodular limestone, in order to test its fitness for use in the proposed breakwater at New Plymouth. I have no hesitation in saying that a first-class cement can be manufactured in that locality at a figure or cost appreciably under what equally good cement can be imported for. The machinery required to start the manufactory would be something as follows :— Two properly-constructed limekilns, say ... ... ... ... £300 Stone-crushing machine and engine ... ... ... ... 700 Grinding-mill ... ... ... ... ... ... 500 Tools, &c, ... ... ... ... ... ... ... 100 Sheds and buildings ... ... ... ... ... ... 2,000 £3,600 From £2,500 to £3,000 would be sufficient outlay to start the undertaking in fair working order, for the local works, and by that expenditure a thorough test and trial as to the paying result could be arrived at without any possibility of doubt. Of course, I assume that the management would be placed under a properly-qualified scientific head. If Dr. Hector could be induced to take the subject up, I believe a great part of the difficulty as to the treatment of the raw materials would be simplified, inasmuch as the chemical analysis of the various stones and clays would be a guide to determine their admixture in proper proportions. A return, also, of the quantity of cement imported into New Zealand each year for the last ten years would be instructive. I have, &c, Chas. D. levine, 9-H. 22.