I remain, Sir,

Your obedient and obliged,
E. A. M.

February 2, 1842.

HINDU PROCESSES OF QUARRYING AND

POLISHING GRANITE.

[We extract the following interesting description of these processes by Lieut. Newbold, from Minutes, in the Athenæum, of the Transactions of the Asiatic Society.]

The most usual mode followed in India is to employ the agency of fire. In this process, the granite rock is covered with dry bushes of the various acacias common on the plains, which are then fired, and kept burning until quite consumed. The intense heat causes a separation or exfoliation of the granite, to the depth, perhaps, of 24 inches, in the centre of the fire, but gradually thinning off towards the edges. The piece thus exfoliated is then detached, by driving in small iron wedges at the extremities, and is finally raised by a powerful lever. Sometimes the rock proves more refractory than usual, and then it is customary to pour cold water upon it when hot, or to drop on the surface a heavy boulder of greenstone or granite. When blocks are required for statuary or mill stones, or for any other purpose where greater thickness than one or two feet is requisite, another process is followed, precisely similar to that employed by the ancient Egyptians in quarrying the granite of Syene. A great number of holes, an inch square, and of different depths, according to the size of the block wanted, are bored in the rock, close to each other, forming a connected chain around the piece to be detached. Each hole is then fitted with an iron wedge, and the whole are simultaneously and unremittingly struck with iron hammers, until their united force overcomes the adhesion of the block. The chisels used in piercing the holes are kept cool, by pouring water upon them while working, as is done in Europe. When long and thinner slabs are required for bridges, pavements, lintels, &c., a third pro

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cess is employed, combining the principles of the two former. The rock is heated, as in the first mode, and the separation is completed by driving wedges into a chain of holes, as in the second. In this way Lieut. Newbold has seen blocks of 80 feet in length separated. He also observed that the Hindus take advantage of the calorific action of the sun's rays, in promoting the separation of the granite slabs; and that they, therefore, select the hot season for their work. He found the temperature of a rock at Dewanconda to be 120°, while that of the surrounding air was only 100° in the sun, and 954 in the shade. Sometimes they pour cold water into the clefts made by the wedges, which greatly hastens the separation of the block. The polish given to Indian granites is at least equal to what is found in Egypt; and good specimens may be seen in the Mausolea of Golconda, at Bejánugger, Galberga, and many other places in the peninsula. To effect this beautiful polish, two processes are followed. When a flat surface is required, the granite is slightly smoothed and flattened by an iron tool; and is then rubbed with a large and heavy block of granite, hollowed on its under surface, and having the hollow filled up by a mixture of lac and corrundum. The mixture adheres strongly to the stone, which is tightly fixed between two rods. The extremities of these rods form the handles for two workmen, who draw the stone backwards and forwards over the block to be polished, occasionally throwing water on the surface, to prevent the lac from melting. When the piece to be polished is of a more varied form, as a cornice or moulding, or figure, a piece of wood, with the corrundum mixture, or even a lump of the mixture alone, is used instead of the granite polisher. Any one who has seen the process will be strongly reminded of it by the paintings at Thebes, representing sculptors polishing a statue, which are copied by Rosellini, and in Wilkinson's "Ancient Egyptians." Lieut. Newbold mentioned a remarkable fact connected with the granite of India; that much of it was in the form of spheroids and bosses, having a concentric laminar structure, like the coats of an onion, which frequently exfoliated by the action of the air, throwing off curved laminæ of very varied magnitude. This exfoliation of mountain masses produces some of the most picturesque features of the Indian landscape. It is the cause of its singular dome-shaped mountains and mamillary masses, crowned with tors which would in England be considered Druidical. Rough sketches of some of these, from Bellary and Bavagudda, were shown to the meeting, strongly resembling the Cheese-ring and Logan-stone, so well

known in Cornwall. The paper concluded with some account of the uses to which granite is applied in India; and a brief notice of the colossal temples and figures, and of the pillars, obelisks, and bridges of this material existing throughout the peninsula.

APPLICATION OF THE ARCHIMEDEAN
SCREW.

Sir,-In your last Number, 965, there is an error of the press, of much consequence to my statement. For 1837, read 1827, which was the year in which I presented my Screw, or "Archimedean" Ship Propeller, to the Lord High Admiral, which he thought proper to reject as quite inapplicable.

I am, Sir, your obedient servant,
F. MACERONE.

THE PECULIAR CASE OF OXYDATION.

Sir,-In Number 963 of your valuable Magazine, a "Constant Reader" wishes to obtain some information respecting a peculiar case of oxydation in a carpenter's stove; I beg leave, through your pages, to give him what knowledge I may have upon the subject: When he has covered the carpenter's stove with plank outside of the flanges, leaving sufficient space for sawdust, he finds the stove to be rusted th of an inch. Now, I think that the sawdust must either be damp, when placed between the iron and the plank, or the steam might possibly get through the flanges, and damp the sawdust, which would then oxydise the iron.

The insertion of the above will oblige your obedient servant.

W.

ABSTRACTS OF SPECIFICATIONS OF ENGLISH

PATENTS RECENTLY ENROlled.

JOHN STEWART, OF WOLVERHAMPTON, Esq., for certain improvements in the construction of piano-fortes.-Enrolment Office, Jan. 7, 1842.

The first of these improvements, which are five in number, consists in forming the frame of metal divided into compartment for the reception of the sounding-boards, which are only connected with the frame at intervals.

The second improvement relates to the mode of constructing and applying soundingboards. These sounding-boards, three in number, are denominated the treble, adapted to the smallest partition of the frame; the tenor, occupying the middle compartments, and a size larger than the former; and the

bass, which is considerably the largest, and is fitted in the remaining partition of the frame.

The third improvement relates to an improved mode of applying the bridges; these are of beech, 4 feet long, and half-an-inch wide at the treble end, gradually widening to three-quarters of an inch at the bass extremity. The bridge is arched into twentyone abutments, each of which rests upon the sounding-board. The pins for the lower frets are placed on the top of the bridge, (which is perfectly straight,) as usual.

The fourth improvement consists in a new mode of stringing, by hanging the wires in small slides fixed in the upper edge of the stud-bar, whence the wires are carried to the pins at the lower edge of the bar, forming the upper frets; the strings then pass down to the bridge in the ordinary way, forming angles between the respective pins placed therein, and after passing below the bridge they are hooked upon steel wires ten inches long, twisted double, with an eye at one end and a hook at the other. The eye is attached to one of the screws of the screw-bar after passing the tension-bar; the other end has a strong steel or iron wire hook, to which a string is attached; it is then turned in the usual manner.

The fifth improvement consists in applying the action to upright piano-fortes, by placing the action underneath the keys, and causing the hammers to strike the wires in two distinct lines. The first line of hammers begins at the highest treble wire, and proceeds gradually downwards beneath the stud-bar to the centre of the scale. The second, or bass line begins at the usual distance from the feet placed on the bridge, and is progressively carried up in an oblique direction to the last note of the bass. A descending wire, or other appropriate connection is adapted to the end of each key, its length being varied to suit the position in which each particular hammer is required to strike its string.

OWEN WILLIAMS, OF BASING-LANE, LONDON, ENGINEER, for improvements in propelling vessels. Enrolment Office, February 4, 1842.

The first of these improvements in propelling is carried out in the following manner :-Two cranks on each end of the engine shaft project beyond the sides of the vessel; to these cranks two rods are jointed, to the lower ends of which floats or paddle-boards of wood or iron are affixed.

Immediately under the crank-shaft are two axes or guides, through which the paddlerods slide freely, the guides at the same time turning in a horizontal direction. These guides act as fulcra, and also regulate the

angle at which the floats enter and leave the water.

A second improvement is intended to take advantage of the pitching and rolling motion of the vessel, and thereby effect its propulsion; for this purpose, two flat horizontal floats, or buoyant surfaces, are placed one under each quarter, and attached to two upright rods or stems. These rods are connected by pin-joints and two parallel bars to the vessel's sides; the rods passing up into the vessel, are there attached to the end of pump levers, which raise and force water out of the stern, and thereby propel the vessel. The floats may either be immersed in the water, or float on its surface, and may be applied, in any convenient position, either to work pumps, or, by the intervention of suitable mechanism, give motion to any kind of propelling apparatus. How much oftener will this delusive scheme be patented?

THOMAS STOPFORD JONES, OF TAVISTOCK-PLACE, RUSSELL-SQUARE, GentleMAN, for certain improvements in machinery for propelling vessels by steam or other power. Enrolment Office, February 4, 1842.

These improvements consist in the employment of two series of cranks for causing the floats or paddles to describe an elliptical path, and to enter and emerge from the water at favourable angles.

For this purpose, a main crank-shaft, of any given throw, projects from the engine shaft, beyond the side of the vessel. Imme. diately over it, but at such a distance as to allow the two cranks to revolve clear of each other, is placed a second crank, having a smaller throw than the former. The neck of the main crank works in a suitable bearing on the upright stem of the paddle or float board, the head or upper part of which stem has a slide drop link groove, within which the brasses in which the upper and smaller crank work slides up and down, as the crank revolves, thereby compensating for the difference between the circles described by each. By this means the paddle or float board is made to describe an elliptical path, and also to enter and quit the water at a favourable angle.

When two or more paddles are employed, they are placed one behind the other, in the direction of the vessel, each paddle stem having a large and small crank, connected together so as to be driven by the main crank shaft of the engine; three of these propellers are shown as thus applied.

The claim is to the two cranks of different throws for each paddle-shaft, and the link and sliding brasses by which the two cranks of different throws are enabled to act in unison, and thus give any degree of an angle that may be

125 preferred to the paddle-boards, both in entering and leaving the water.

JAMES WARREN, OF MONTAGUE-TERRACE, MILE-END-ROAD, for an improved machine for making screws. Enrolment Office, February 4, 1842.

The object of this invention is the enabling of moulds for casting screws to be made in moulding sand, by screwing patterns of the screws therein, and then withdrawing them by unscrewing, so as to leave patterns of such screws impressed in the sand, or such like material. Two rails, or tramways, are fixed lengthways on the top of a strong bench, upon which a plate of iron traverses to and fro, by means of four small wheels or rollers. A moulding head plate, having the patterns of the heads of the screws upon it, and properly gitted and sprayed, is placed in the sand tub, and a moveable iron mouldingbox placed upon it; this box is then filled with sand, slightly pressed and levelled. A board is then laid on the top of the box, the usual way, and turned over, when the upper part of the sand will retain the impressions of the heads of the intended screws, and also of the gits and sprays. This box is then placed upon the iron plate on the carriage, with the patterns upward, and rolled under a screwing frame; three plates, the head plate, the steadying plate, and the guide screw plate, are brought down upon the moulding box, and secured there by studs. Each of these three plates contains as many holes as there are patterns used in the machine. In the upper part of the machine there are three cog-wheels, which are worked by turning a handle affixed to the middle one, and give motion to the outer two, to which the motion cranks are attached; these cranks give motion to a crank-plate, having the same number of holes as there are patterns employed. Each of the pattern screws terminates at top in a crank, which takes into the crank plate, so that on giving motion to the working cranks, all the screws are simultaneously turned round and screwed into the sand, by means of suitable guide-screws, &c. On reversing the motion, they are unscrewed and withdrawn, leaving the pattern of the screw impressed in the moulding sand. The screwing-frame is then raised, and the moulding-box drawn out, to make room for another. A corresponding moulding-box being filled with sand, its smooth surface is placed upon the impressed surface of the first, and being clamped together, the fluid metal is poured in. When the boxes are separated, the screws will be found perfect, except the nick or slit in the heads, which may be made with a circular saw, in the usual way; or the nicks may be cast in the heads of large screws, by making them in the patterns.

RECENT AMERICAN PATENTS. [Selected and abridged from the Franklin Journal.]

HORSE POWER FOR DRIVING MACHINERY; George Strenge and Jacob Rohrer. This is for an improvement in that kind of horse power in which the power is applied, by causing the horse to walk in a circle, and to draw by means of a lever or sweep attached to a vertical shaft; and it consists in the peculiar manner in which the levers or sweeps are attached to the main driving wheel. The patentees observe, that "sweeps of this description have heretofore been fastened to the main shaft, in such a manner as not to allow of their having any vertical play, in consequence of which, a considerable portion of the power of the horse or horses has been expended without the production of any useful effect, and has, in fact, been productive of injury, by racking the machine." In this machine the sweeps pass through staples attached to the main wheel, which staples are so formed as to confine the sweeps laterally, whilst they are allowed to play vertically. The inner end of the sweeps are received within mortises in the upper end of the shaft, and there are springs on the upper and lower sides of the rear ends of the sweeps, which bear respectively upon the main driving wheel and upon the upper part of the staples. The upper springs are provided with an off-set to operate as a latch in confining the sweeps in place.

STOPPING LEAKS IN HOSE; Ralph Bulkley. This patent is taken for a mode of stopping breaches in leather hose, whether small or large. Small breaches, or holes, are to be closed by a conical screw plug with a flat head. The point of the screw is to be inserted in the aperture, which, by screwing, is gradually enlarged, embracing the screw until the water is prevented from flowing out. But if the aperture be a slit passing lengthwise, it may be temporarily repaired for use by two corresponding plates of metal, the one to be placed inside of the aperture, and of sufficient length to cover it, there being a corresponding plate upon the outside of the aperture; the two plates are to be drawn together by screws, previously fitted to them, thus firmly binding the edges of the leather between the said plates of metal. If the aperture be so large, or of a description that it cannot be secured by such screws or plates, then a section of metal, or other description of pipe or tube, of suitable dimensions, may be inserted within the defective part, and the apparatus denominated "breach clogs" is to be applied thereto; but if the breach required to be stopped be not in itself large enough to admit of the application of the "breach clogs," the water hose may be

severed by cutting it entirely across, or incisions of suitable extent may be made for the convenient and necessary application of the said apparatus. The claim is to the "mode of repairing lateral breaches in hose by means of screws, as set forth. Also of repairing larger breaches in the same by means of metallic plates and flexible tubes, inserted in hose, constructed and secured in the manner described."

IMPROVEMENT IN RIFLES AND OTHER FIRE-ARMS; James R. Thomas. This patent was granted for an improvement on that kind of guns in which a separate chamber, removeable from the barrel, is used. The separate chamber is made with a projection around the forward end of the bore, which fits into a recess in the barrel, the breech of the gun being made to receive the said chamber. Near the top of the back end, the chamber is provided with a hole, which receives the end of a spring bolt to hold it in place. The spring bolt is drawn back by a projection from the tumbler, which acts against an offset on the bolt, so that in bringing the hammer to the half-cock, the spring bolt is drawn out clear of the hole in the back of the chamber, and on cocking, the projection on the tumbler clears the offset on the bolt, and allows it to return by the action of a spiral spring coiled around it. A part of the lower part of the back of the chamber is bevelled off, so that in putting in the chamber, the bevelled part will force back the spring bolt until the chamber is in place. When the hammer is at half-cock, the chamber is forced up out of its place by a pin passing through a hole in the bottom of the case which receives the chamber; this pin is attached to the end of a spring screwed to the under side of the barrel.

EVAPORATING SOLUTIONS, DECOCTIONS, &c., FOR THE PURPOSE OF CONCENTRATING THEM; James W. W. Gordon. The patentee says, "The object of my improvement is principally to obviate the danger of injuring the preparation, which in articles of great delicacy sometimes takes place, by the application of the heat of a water or steam bath only; and this I effect by means of a machine which produces rapid evaporation at the ordinary temperature of the atmosphere."

FLYER FOR TWISTING SILK, &c., Edward L. Young. This flyer, instead of having two guide wires run out their whole length parallel to, and at equal distances from the axis, has one short and one long guide wire-the short wire, or arm, extends as far only as the middle of the bobbin, and the longer arm extends to some distance beyond the end of the bobbin, and is there

curved so as to bring the guide in a line with the axis of the bobbin-the guide wire being sufficiently long to admit of putting on and taking off the bobbin without moving the flyer. A ring is attached to the two guide wires of this flyer, near the extreme end of the short arm, to prevent the centrifugal force from throwing out the guide wires which constitute the flyer.

The claim is to the method of construct

ing the flyer.

FIRE ARMS; Silas Day. This patent is obtained for an improvement on that kind of fire arms that load at the breech, and it consists in making a curved chamber at the breech, which opens at the side of the barrel, for the reception of the load. The side aperture is closed by a valve which works on a pin and is provided with a handle and catch; the valve works in a slot made in a block of iron that projects from the side of the barrel, and in which block a part of the curved chamber is made.

"I am aware," says the patentee, "that guns have been made to load at the breech by having a sliding valve to close the aperture through which the charge is inserted, but not constructed like the plan herein described, and therefore I do not claim the principle of loading at the breech as my invention, but what I do claim as my invention, and desire to secure by letters patent, is the curved chamber, and in combination therewith the sliding valve and its appendages, consisting of the slot and lever, for the purpose, and in the manner herein described.

CUTTING SCREWS ON THE RAILS OF BEDSTEADS; Jacob Lindley. The ordinary method of cutting screws upon the ends of bedstead rails, is well known to all who are acquainted with the making of such articles. In the improved mode, the rail is held in the middle by a clamp attached to a bench, on each end of which there is a puppet head in which works a screw, mandrel, or shaft, provided with a winch on its outer end, and on the inner end of each of these is fitted a socket, very similar to those usually employed for cutting wooden screws, excepting that they are made of steel, and the cutter is formed by it, instead of being attached thereto. These sockets are fitted on to the inner ends of the screw, mandrel, or shaft, by a socket, and secured by a thumb screw, by means of which the precise point at which the threads, on each end of the rail shall end, can be regulated. That end of the socket, on which the cutter is situated, is bevelled off, and the cutter is so formed as to cut under the shoulder.

The claim is to the "manner of forming

127

the cutters for cutting the screws on the ends of the rails, by making them a part of, and one with, the sockets, or female screws. Also, the manner in which I have combined and arranged these sockets, the screw shafts, and standards (puppets) with each other, for the purpose set forth."

MACHINE FOR CUTTING CORK; Charles R. Macy. The pieces of cork, called blocks, cut into proper lengths, are held between two revolving spindles which grip them, and as they revolve, the cork is cut round by a revolving cutter wheel, the arbor of which is horizontal and has its bearings in a sliding frame. This frame rests upon two cams, on a shaft parallel to, and under the shaft of the cutter wheel, the cams being of such form as that at the commencement of each operation the frame and knife will be lifted up, and cause the edge of the cutter wheel to approach the piece of cork to be cut, and when the cork has been cut, the frame and cutter wheel are let down to allow the revolving gripes to receive another block. The edge of the cutter wheel is kept sharp during the operation, by means of two rotary disks, one acting on each face. The faces of these disks are covered with leather, and emery, or any other substance which will give an edge. As the cutter wheel revolves, to cut the cork, every part of its edge is brought round to these grinding disks. The blocks are fed in through a box, from which they are taken by a jaw which slides forward and places them between the gripes of the revolving spindles.

The claim is, first, to the "combination of the rotary cutter wheels with the sharpening rotary disks, one on each face of the rotary cutter for the purpose and in the manner described.

Secondly, to the method of moving the rotary cutter wheel up and down at the commencement and end of every operation by means of the sliding frame, acted upon by the cams, for the purpose and in the manner described.

"And thirdly, to the method of feeding the machine with the block by means of the slide and jaw, in combination with the receiving box and spindles as herein described."

The attempts at cutting corks by machinery have been numerous, and have uniformly proved failures; not that corks have not been cut by machinery, but because they have not been so well cut as by hand, and because the preparing and assorting of the blocks to be cut by the machine have required a degree of care and attention which are not repaid by the result.

IMPROVEMENT IN THE MANUFACTURING OF CLOTHS OF WOOL, OR WOOL AND SILK;