Mr. Parkes has also taken out a patent for a varnish made of gun cotton dissolved in alcohol, or any solvent of gun cotton. This varnish is transparent, and he applies it to coat silk, sewing cotton, thread, leather, plaster, wood, &c., to render them water-proof. Gun cotton dissolved in chloroform is a well known varnish.
INDIA-RUBBER TEETH.
This article, in the form of purified white India-rubber, has been patented in England, for making artificial teeth, gums, and palates. By its adoption, many advantages hitherto impossible to be attained, have been introduced. The adhesion is complete, it can be moulded with perfection, to suit every inequality of the gums and teeth, and supplies an artificial periosteum, as it were, to the teeth, when become painful by the wasting away of the gum, added to these is the elasticity of the material, which completely obviates the inconveniences that arise from any motion with artificial teeth, as made by other means.
EMERY PAPER.
The Moniteur Industriel mentions an ingenious method of obtaining fine emery paper for polishing metals. Strips of paper coated with fresh starch-size are hung on ropes at different altitudes in a small room, which is afterwards carefully closed. A quantity of fine emery is then blown in by means of a ventilator, through an aperture left for the purpose, by which means a dense cloud of emery dust fills the room, but only the finest particles rise in the air to a sufficient height for them to be deposited on the upper slips; those of the second row receive a somewhat coarser sort, and so on, while such particles as are too heavy, and therefore too coarse for delicate polish, fall to the ground at once. Thus emery paper of different degrees of fineness may be obtained by a single operation, and sorted with mathematical certainty.
SULPHURIZED OIL PAINT.
At a recent meeting of the Society of British Architects, J. B. Daines stated that by subjecting eight parts (by weight) of linseed oil and one part of sulphur, to a temperature of 278°, in an iron vessel, he obtained a species of paint possessing singularly preservative properties. Applied to the surface of a building with a brush, it effectually keeps out air and moisture, prevents deposits of soot and dirt, and preserves the beauty of the stone, wood, or brickwork to which it is applied. It has long been known that a portion of sulphur can be dissolved in oil, but until recently such a composition, as a paint or varnish, has attracted no notice; in fact, its preservative and impervious qualities when dry, were unknown. It is well known to chemists that sulphur, (the substance employed to give body to the oil,) is unalterable in the air, and is not acted on by moisture; hence its quality as a preservative for coating the outside of structures exposed to the weather. It is capable of preserving plaster of Paris figures exposed to the air, also monuments, and buildings of the brown freestone, which are liable to detrition, from the action of the weather. It is stated that it improves the color of the stone to which it is applied, as well as preserves it; therefore it is a most useful paint, and deserves to be very generally employed.
INDIA-RUBBER AND COAL TAR.
Mr. C. Goodyear has recently taken out a patent in England, for a new compound, composed of India-rubber and coal tar vulcanized with sulphur. Coal tar is heated in an open boiler until it acquires the consistency of melted rosin, when it is mixed with India-rubber, in proportions which may vary according to the character of the material to be produced for a specific purpose. It is mixed with sulphur and then heated to vulcanize it.