7. The cost of this purification is covered sufficiently by the above advantages, and besides this, the method is cheaper and surer than any other.
The chemical factory, Eisenbuettel, furnishes pure carbonate of soda in single packages, which exactly correspond with the quantity, stated by the analysis, of ten cubic meters of a certain water. The determination of the quantities of lime and carbonate of soda necessary for a certain kind of water, after sending in a sample, will be done without extra charge.--Neue Zeitung fur Ruebenzucker Industrie.
EDDYSTONE LIGHTHOUSE.
The exterior work on the new Eddystone Lighthouse is about two thirds done. In the latter part of April fifty-three courses of granite masonry, rising to the height of seventy feet above high water, had been laid, and thirty-six courses remained to be set. The old lighthouse had been already overtopped. As the work advances toward completion the question arises: What shall be done with John Smeaton's famous tower, which has done such admirable service for 120 years? One proposition is to take it down to the level of the top of the solid portion, and leave the rest as a perpetual memorial of the great work which Smeaton accomplished in the face of obstacles vastly greater than those which confront the modern architect. The London News says: "Were Smeaton's beautiful tower to be literally consigned to the waves, we should regard the act as a national calamity, not to say scandal; and, if public funds are not available for its conservation, we trust that private zeal and munificence may be relied on to save from destruction so interesting a relic. It certainly could not cost much to convey the building in sections to the mainland, and there, on some suitable spot, to re-erect it as a national tribute to the genius of its great architect." When the present lighthouse was built one of the chief difficulties was in getting the building materials to the spot. They were conveyed from Millbay in small sailing vessels, which often beat about for days before they could effect a landing at the Eddystone rocks, so that each arrival called out the special gratitude of Smeaton.
ROLLING-MILL FOR MAKING CORRUGATED IRON.
MESSRS. SCHULZ, KNAUDT & Co., of Essen, who are making an application of corrugated iron in the construction of the interior flues of steam boilers, have devised a new mill for the manufacture of this form of iron plates, and which is represented in the accompanying cut, taken from the Deutsche Industrie Zeitung. The supports of the two accessory cylinders, F F, rest on two slides, G G, which move along the oblique guides, H H. As a consequence of this arrangement, when the cylinders, F F, are caused to approach the cylinder, D, both are raised at the same instant.