The great importance of the manufacture of bone fertilizers, the value of which is daily becoming better appreciated, and the great number of other purposes to which bones are applied in the arts, give interest to any device employed in their utilization. The reader will find on page 137, Vol. XX., of the SCIENTIFIC AMERICAN, an article on the " Value of Bones," and another on the " Utilization of Bones," on page 873, of the same volume, to which he is referred in this connection. We illustrate herewith a machine for grinding bones, which has, although but recently introduced, attained an excellent reputation for its efficiency and other good qualities. An examination will satisfy all practical minds that the de-Yices employed must secure good work. Fig. 1 is an elevation of this mill, a vertical section of which is shown in Pig. 2. D is the hopper with a gate to adjust the feed. When in use the bones fall from this hopper down upon a powerful breaker or cracker at the bottom of the chute. Prom thence the crushed fragments pass in between the grinding plates, one of which is stationary and the other revolving. The revolting plate is made so as to conform to the shape of the stationary grinding plate, which latter has the form of the mouth of a trumpet. A screw, lever, and hand wheel, A, serve to adjust the revolving grinding plate, so that it will grind to any required fineness. 'The revolving grinding plate is made of two metallic sections, an external one, B, and an internal one, C, which latter is the grinding plate proper. Between the sections, B and C, is a section of non-conducting packing, the object of which is to keep the mill from heating. The stationary grinding plate is also backed with similar packing for the same purpose. Fans are also attached to the periphery of the revolving grinding plate, by which, together with the non-conducting packing, the mill is essentially prevented from heating. The breaker, or cracker, is formed by strong studs projecting from the shaft of the revolving grinding plate playing [jetween other studs, or teeth, projecting from the inside of the outer shell of the mill. This part is very distinctly shown in the engraving. The peculiar " dress" of this mill consists of hollow diamond-shaped projections, radiating in lines from the center to the periphery of the plate. These grinding teeth are of hard iron from one eighth of an inch to three sixteenths of an inch in hight, thus making from one quarter to three eighths of an inch of hard iron on both plates, which will last a long time. This structure of the grinding plates renders the teeth self-sharpening. When dulled by use after running the mill in one direction, they are sharpened for the other direction, so that all that is required is to reverse the motion of the mill. These surfaces are also made in segments so they can be easily removed for repairs, or, if necessary, replaced. Thus an important advantage is gained over the burr stone mill; namely, the obviation of all necessity for " dressing." This principle has been successfully extended by the inventor to mills for nearly all grinding purposes. A patent was obtained on this invention July 14th, 1868. A reissue was granted September 15th, 1868, and patents on other improvements are now pending. For further information address Henry Shaw, agent, Diamond Mill Co., Cincinnati, Ohio. A Very old Invention. There is an old book, and a very scarce book now, bearing on its title page the following : " Mechanick Powers : or, the Mistery of Nature and Art Unvail'd. Showing what Great Things may be performed by Mechanick Engines, in removing and raising bodies of vast Weights with little strength, or force; and also the making of Machines, or Engines, for raising of Water, draining of Grounds, and several other Uses. Together with a Treatise of Circular Motion artificially fitted to Mechanick use, and the making of clockwork, and other Engins. A work pleasant and profitable to all sorts of Men from the highest to the lowest Degree; and never treated of in English but once before, and that but briefly. The whole comprised in Ten Books and illustrated with Copper Cuts. By Ven.Mandey and J. Moxon, Philomat. London: Printed for the Authors, and Sold by Ven. Mandey, next door to the Salmon, in Bloomsbury Market, and James Moxon, at the Atlas, in Warwick-lane, and R. Clavel, at the Peacock, in Fleet-street, 1696." This book is dedicated to his Grace, William Duke of Bedford, at that time Lord-Lieutenant of Middlesex, Cambridge, and Bedford, by his humble servants, Venterus Mandey and James Moxon, and contains much quaint matter. It claims to be the first treatise on mechanics written in English, with the exoeption of the work by one Bishop Wilkins, who wrote " but briefly, and rather historically than fundamentally." Among descriptions of " En-gins moved by Smoak," of apparatus for indicating the distance traveled by a chariot or ship, of the effect of percussion or smiteing, we find the specification of a wire tramway, identical in principle with tfcat of which we have lately heard as a bran new invention, working successfully among the Leicestershire quarries : " ENOHN VI. To REMOVE A MOUNTAIN, OR HEAP OF EAKTH, FROM ONE PLACE TO ANOTHER EASILY AND QUICKLY. " Let the mountain, or hill, or heap of stones be A, to be removed to the place B; to save time in going and returning from one place to the other, as also that the motion whereby the earth or stones is transferred from A to B may 'oe swift, we may make use of the following industry : Erect at the foot of the mountain, or in its middle, a great and solid wooden column, or piece of timber, C D, and erect such another in B, namely, E F, affix at the top of each piece or column, the wheels, D and F, and make hollow each wheel in the circumference; and put about them a great strong rope, extended parallel to the horizon; but if the distance from A to B be great, least the rope should be too much stretched or bent, raise other such like pieces, or columns, in the middle with their wheels made hollow as aforesaid, to sustain the rope parallel to the horizon; on the rope thus doubled, here and there hang baskets, which must be so far distant from each other, that they hinder not one another; and the ends of the pieces must be so placed, that the power applied to the leavers, (1 and H, may be turned about their centers; for so the whole rope, with the baskets hanging on it, will be turned about successively; wherefore, if men keep filling the baskets in A, and others unload them inB, the whole hill will be easily transferred from A to B. " Where note, that the greater the wheels D and F are, the swifter the rope and baskets will be turned about, which mo-motion about the axis or piece of timber being easie, may be accomplisht by means of short leavers, and so the motion of the baskets may be greater than the motion of the power about the piece of the timber. Besides the saving of labour, and the gaining of time, which is effected by this engin, it hath likewise this conveniency, that if betweenthe two places, A and B, there should be a river, or stream, or such like in- accessible, as if the earth were tobe transferred from a mound, or hill, to the next adjoining field, and there were a large deep mote or ditch before them, you could scarcaly obtain your desire any other way." Venterus Mandey and James Moxon, Pliilomat, were thus nearly two hundred years in advance of the recent inventor of the wire tramway.—Engineering. (For the Scientific American.)