The following inventions have been patented this week, as will be found by referring to our List of Claims :— SAW GRINDING APPARATUS—The object of this invention (which has been patented in England as well as in the United States) is to grind circular saws to a uniform thickness and with their faces perfectly even or free from the wavy appearance so frequently produced by some of the methods of grinding heretofore practiced, and to finish them perfectly to the center or eye. The invention consists in grinding the one side of a saw at a time, while the opposite side is supported by a roll which has a rotary motion at the requisite speed to cause the revolution of the saw as desired. A rotating friction clamp is applied to the saw during the grinding process in such a manner that it derives rotary motion from the saw through the agency of friction, and by the momentum acquired by such rotary motion, is caused to control and render uniform the velocity of rotation of the saw, notwithstanding any difference in the thickness of the saw plate, and consequent tendency to variation in the action of the feed roll, or other feeding contrivance upon the thicker and thinner portions of the plate. The saw is arranged to rotate in and during the grinding process upon a flat pivot, which is of sufficient width in one direction to fill the eye of the saw and steady the same as it rotates, and this is thin enough in a transverse direction to permit the grindstone to operate over the whole surface of the saw. W. Clemson, of East Wo-burn, Mass., is the inventor. BOILER FEED REGULATOR.—The kind of regulator to which this invention relates, consists of a cock in the feed pipe at or near its junction with the boiler, and an attached float resting on the surface of the water in the boiler, and operating to open and close the passage through the cock as the level of the water in the boiler varies, for the purpose of admitting or shutting off the supply of water. The cock and float constitute the whole apparatus for feeding a boiler for heating purposes, of so Iowa pressure that the pressure of water in the supply pipes of cities or the head in an elevated reservoir is sufficient to force in the water, but when the water has to be pumped into the boiler, the inventor generally attaches a lever to the cock to start the feed pump when more water is required in the boiler. The improvement of this inventor— Leonard Thorn, of New York—consists in the peculiar manner of combining the float with the cock, whereby the regulator is made of simple construction and very efficient. SUBSTITUTE FOR LEATHER.—Samuel Whit-marsh, of Northampton, Mass., has invented a new fabric which is intended to supply the place of leather in many of its applications. The fabric is composed of cotton or other fibrous substances either woven into cloth or in an unwoven state, and saturated or coated with a compound of linseed oil and burnt umber prepared by boiling in every gallon of oil about three pounds of umber in a powdered state, for such a length of time, that the composition when cool will roll in the hands without sticking. The fabric may be made in forms suitable for the soles of boots and shoes, coverings for trunks, traveling bags, cap fronts, or as a substitute for carriage or harness leather, or for machine belting or hose pipe. The mode of producing the fabric differs to some extent according to the use for which it is designed, but the general principles are in all cases the same. The umbei is stirred into the boiled oil until it reaches the point desired, when it is ready to be applied in the manner best calculated to produce special articles. This patent is owned by the New York and Northampton Belting and Hose Company, who have secured patents in Europe. SMOKE CONSUMING APPARATUS.—This invention consists in the construction and arrangement of an apparatus for separating the combustible from the incombustible gases which are the products of the partial combustion in a furnace, in such a form as to make the apparatus applicable to all steam boilers or other furnaces and stoves. A chamber is constructed behind or in any convenient situation close to the furnace, and through this chamber the mixed gases pass; the heavier ones such as carbonic acid, being incombustible, pass by a bottom flue to the chimney, while the lighter ones, such as carbonic oxyd, are said to pass by an upper flue back into the furnace, thereto be consumed. W. Davidson Jones, of Hagamans Mills, N. Y., is the inventor. COMPOSITION FOR JAPANNED LEATHER.— The cempounds commonly employed for the first, or first and second coats, in the manufacture of glazed or j apanned leather or cloth, is made by boiling a certain quantity of umber in linseed oil, and adding a quantity of lampblack or other coloring matter with a quantity of camphene or spirits of turpentine about equal to one and a half times that of the linseed oil. O. S. Boyden and M. Fredericks, of Newark, N. J., have invented an improvement on the above composition, which consists in the substitution either wholly or in part for the camphene or spirits of turpentine in the compound, of a paste made by boiling flaxseed, either whole or after the oil has been expressed, and either ground into meal or unground, in water till its glutinous property is extracted. The use of this paste as a substitute for camphene and spirits of turpentine not only reduces the cost of the compound, but also renders the goods more pliable and less likely to crack. IMPROVED FURNACE GRATE.—A. J. Allen 8c W. S. Hudson, of Paterson, N. J., have invented an improvement in the bars of furnace grates which enables them to have a limited upward and downward movement, and by that means break up all "clinkers" or other foreign substances which interfere with the draft, and also affords facility for their passing through into the ash pit. The fuel is also distributed evenly over the bars, and thus the fire is kept more equal and likely to burn its smoke. The invention is applicable to furnaces using any kind of fuel, but is more particularly intended for the use of anthracite or bituminous coal, and may be used with especial advantage in coal-burning locomotives. APPARATUS FOR DISTILLING TURPENTINE. —The chief feature of novelty in this apparatus is an important one; it consists in having a chamber above the still, in which the barrels of crude turpentine are placed, having first been unheaded, and steam being admitted into the chamber, all turpentine is melted from the barrels and runs into the still. This effects a saving, as in all other apparatus the crude turpentine is scraped from the barrel, and consequently some must be wasted. The still is heated by steam, so that the fire in no place comes in contact with the inflammable material, and the danger of explosion is avoided. Daniel Reid, of Washington, N. C, is the inventor. HYGROMETER.—This invention relates to that description of hygrometer composed of a twisted cord of catgut or other substance which is caused to untwist and twist itself up by the increase or diminution of its bulk produced by changes in the hygrometric condition of the atmosphere. The improvement of this inventor—Chas. L. Clarke, of Rochester, N. Y.—consists in certain means of combining the cord with an index so that an hygrometer of this kind will serve as a weather glass. THERMOMETER.—S. Holton, Jr., of Middle-bury, Vt., has invented a useful improvement in metallic thermometers so that the pointer I is made to indicate correctly upon a dial, the) variations in temperature.