The machinery at the Royal Dock-yard, at Portsmouth, invented by Mr. Brunei, for manufacturing blocks, is deservedly celebrated. The following is a concise account of it. The machines are separated into four classes. 1. The sawing machine, for converting the large timber into proper dimensions for the small machines to operate upon. 2. The machinery to form the shell. 3. The sheave-forming machines. And 4. The pin-forming machines. The machinery is capable of completing three sets of blocks of different sizes at the same time, and is worked by two steam-engines of 30-horse power each. The order of the process is this: the elm trees are first cut into short lengths proper to form the various sizes of the blocks, by two large sawing machines, one a reciprocating, and the other a circular saw. These lengths of trees are next cut into squares, and ripped or split up into proper sizes by four sawing benches, with circular saws, and one very large reciprocating saw, which is employed in cutting up the pieces for very large blocks.

The scantlings of the blocks being thus prepared, the next process is that of Making the Shells.

The centre hole for the pin of the sheave is first bored by a centre bit in the boring machine, whilst a number of others, corresponding to the number of sheaves which the block is to contain, is bored at right angles to the former, to admit the first stroke of the chisel, and, at the same time, form the head of the mortises. The blocks are then removed to the mortising machine; here they are firmly fixed to a movable carriage, beneath cutting chisels, set in a frame moving up and down with extreme rapidity, making, according to Dr. Gregory, 400 strokes per minute. Each time that the chisel frame ascends, the moving carriage advances a small space, bringing a fresh portion of wood under the chisel, until the mortise is cut to the proper length, when the machine is stopped with the chisel frame at its highest elevation. The chips cut are thrust out of the mortise by small pieces of steel projecting fr6m the back of the chisels, which are also armed with two cutters, called scribes, placed at right angles to the chisels, which mark out the breadth of the chip to be cut at each stroke, and at the same time leave the sides of the mortise so true as to require no further trimming.

The corners of the block are next taken off at a circular saw table, and it is then removed to the shaping machine; here the blocks are fixed in grooves in the peripheries of two equal wheels fixed upon the same axis, the distance between them admitting of regulation to suit various sizes of blocks, each wheel having ten grooves, so that ten blocks are shaping at once. These wheels are made to revolve with great velocity against a cutter set in a slide rest, which, moving in a curved direction to the line of the axis, cuts those outward faces of the block to their required figure. As soon as the tool has traversed the whole length of the block, the machine is thrown out of gear, and the blocks are (without removing them) each turned one-fourth part round, and another fourth-part of their surface is exposed to the cutter. When the remaining portions of the surface are shaped, the ten blocks are removed, and the last operation is performed by the scoring machine, which, by means of a cutter, scoops out a groove round the longest diameter of the block deepest at the ends, and vanishing at the central hole for the pin. There only remains to remove any little roughnesses, and give the surface a kind of polish, which is done by hand, and the shell is then complete. Of the Sheaves.

These are mostly made of lignum vitae, which is cut into slabs of a proper thickness by circular saws, and then removed to a crown saw, which bores the centre hole, and at the same time reduces the circumference to a circular figure. The sheave is then placed in the coaking machine, which forms a recess on each side of the block to receive the bush or coak, which is a triangular form, with the ends rounded off. The machinery for effecting this is extremely ingenious, and acts with such accuracy, and the coaks are cast so true, that a single tap with a hammer is sufficient to fix the coak in its place. Three holes are then drilled through the two coaks and the intervening wood, and pins being inserted in the holes, they are placed under the riveting hammer, which strikes the pins with a velocity proportioned to the pressure which the workman exerts upon the treadle. The centres of the coaks are next broached by a steel drill, and the sheave being removed to a lathe, which cuts the groove on the periphery whilst it faces the sides, the sheave is completed. There remains now only the iron pin, which, passing through the two sides of the shell, serves as the axis on which the sheave turns.

These pins are also made, turned, and polished, by a machine for the purpose; so that, with the exception of strapping by rope or iron, the block is now complete. The whole cost of the machinery, steam-engine, buildings, interest of money, etc. was 53,000f., and which, by the saving effected by the machine, was completely cleared in four years: Mr. Brunei received on the whole about 20,000f. It is calculated that the machine made 140,000 blocks of various descriptions per annum, from the year 1808 to the conclusion of the war, which was found to be not only sufficient for the service of the navy, but also of the ordnance department.

Although the foregoing account of the operations of the several machines will convey to the intelligent reader a sufficiently clear idea of the whole process by which the blocks are made, we doubt not that a representation of some of the principal machines will be acceptable to our readers. To give engravings of the whole of them would cause us to extend this article to too great a length; as, independently of the various saws by which the trees are cut up into blocks and slabs of the proper dimensions, (which saws may be considered as applicable to other purposes), there are a great variety of machines employed in the subsequent operations. These may be said to constitute the block-making machinery, properly so called; and from these we have selected two of the principal, to form the subject of the accompanying engravings. Fig. 1 is a side elevation of the mortising machine, in which the mortises for the sheaves are cut. a a the bed of the machine; b a sliding carriage; c the block to be mortised, securely held in the sliding carriage by the screw e; f one of the cutters, the number of which depend on the number of sheaves the block is to contain; g the cutter frame, moving vertically in guides fastened to the two front pillars of the machine, one of which pillars is removed in the figure, in order to show the cutter frame; h a guide rod attached to the upper part of the cutter frame, and moving in a collar j; k connecting rod, attached at the upper end to the cutter frame, and at the crank l fixed upon the shaft m, which is driven by a strap from the steam-engine passing round the drum n, which is bolted to the flywheel o.