Mechanical an Useful arts. Merble Veneering, or Slaty Paint.

The Year-Book of Facts in Science and Art
Exhibiting the Most Important discoveries and Improvements of the past year,
in mechanics and the useful arts; natural philosophy; electricity; chemistry; zoology and biology; geology and geography; meteorology and astronomy.
By John Timbs,
editor of "the Arcana of Science and Art."
London:
David Bogue, Fleet Street,
MDCCCXLIX (1849)In Ohio, according to a New York paper, a Mr. Blake, of Akron, has discovered a curious mineral, soft at first, and like indigo, but hardening in a few days into a slaty stone. On analysis, it is found to consist of about one-half silica, one-fourth alumina, with magnesia, oxide and sulphate of iron, lime, and carbon. By reducing it to fine powder, mixing with linseed oil into thick paint, and applying it with a brush to wood, iron, tin, zinc, or brick, it becomes, after a few months’ exposure, perfectly hard and indestructible. As a protection against fire, it is said to be invaluable. In the west it is in large demand for covering roofs of buildings, for bridges and fences, &c., all of which it protects from weather as well as from fire. School slates are manufactured by applying it to thin wood or pasteboard. On wooden mantel fronts and tables its appearance, when polished, is held to be not inferior to the finest Egyptian marble. Mr. Blake has procured a patent for his discovery. Would not Portland cement, in fine powder, and thus applied, with linseed oil, produce a slaty veneer over similar surfaces? We make a present of the suggestion to the Portland cement manufacturers. Parian cement mixes with oil, and might thus, we think, be used as paint, or for stony veneering; and certainly the surface of blocks of Portland cement reminds one a good deal of slate: the hardening, too, from a soft or moist state very much adds to the resemblance which it bears to this new world’s wonder. Silica, with lime, has been found, if we mistake not, to form a sort of glaze well adapted to give a stony veneering, like this, to plaster.

— Builder, No. 298.