A specimen of cast-iron plates for roofing of buildings, says the Philadelphia Ledger, has been exhibited at the Exchange, in Philadelphia, by the inventor and patentee, Mr. Wm. Beach. The plates are about a foot square, and are made to fit one into another so as to render the roof perfectly water-tight, with the application of white lead to the joints. In every respect this material for roofing is preferable to any other description now in use. As to its durability, there can be no doubt that it would remain perfectly whole for ages, if covered occasionally with a coat of paint, and even without that preservative, rust would not affect it materially for a period of fifty years at least. As compared with copper, the cost would be nearly one half, as it is expected the iron can be furnished at 16 cents per square foot, while copper would at the most moderate estimate cost 28 cents. As regards the weight of an iron roof, which at first sight would appear an objection, it is far less than one formed of slate, and does not much exceed one of copper. The iron plates weigh three and a half pounds per square foot. A slate roof would cost about eight cents per square foot, but for durability, and the ease with which it can be put on and made water tight, the iron roofing would appear to be far preferable. The plates exhibited were cast at Troy, New York, and are of the very best quality. The patent for the eastern States is now owned by Mr. Hiram Hemmistone, of Troy, in which neighborhood the adaptation of such a durable material for roofing is rapidly attracting public attention there. Starbuck's machine shop and foundry at Troy has been covered on this plan, and it has also been adopted for the roofing of an arsenal at West Point.
[The New and Wonderful Pavement.]
We presented in a late number, a brief extract from an article on this subject from the "Eureka," and should have thought no more of it, had we not observed the following notice editorial in the N, Y. Farmer and Mechanic. We copy the article entire, that our readers may judge for themselves whether the style and statements savor most of reality or humbug.
"New Pavements.--A new system of making streets has been made known to us;--but as it will be the subject of Patents, here and in Europe, we can only give some of its most prominent features. A material or composition, of a very cheap character, has been invented, as hard, strong and compact as flint. It is formed into any desirable shape in the course of manufacture. From this, streets of any grade may be formed, and in such a way as to entirely secure a permanent and level surface to its proper arch; it can be taken up in five minutes, so as to get at the water pipes, and on being replaced will, from necessity, resume its first position. In durability, it will last ten times as long as granite, and twenty times as long as the common paving, without liability to require repair. It is so laid that frost and storms cannot affect it. But we shall have occasion to refer to it again".--Persons wishing information may inquire of Kingsley & Pirsson, No. 5 Wall street.
[To render Shingles Durable.]
One of our exchanges mentions an experiment which was made twenty-seven years ago, of dipping shingles into hot linseed oil prior to nailing them on the roof: and although they have not been painted, they are said to continue perfectly sound as when first put on. They were of the common pine, and as much exposed as roofs in general. This instance may be sufficient to establish the fact that shingles thus prepared, will last longer without painting than they could possibly be preserved by painting in the usual way. As a security against fire, however, we should recommend that they be first dipped in a hot solution of common salt; and afterward, when dry, be dipped in the hot oil. The expense will be trifling, and there can be no doubt of their durability, and there will be no danger of their taking fire from sparks or cinders.