BLOCK MACHINERY. The vast number of blocks constantly required for the use of the English navy and the mercantile marine of this country may be understood from the fact, that upwards of 1400 blocks of all sorts are needed for fitting one ship of 74 guns ; while for smaller vessels, although the sizes may be different, the number will not mate rially vary from what is here stated. These blocks are a kind of pulley, for fastening and guiding the rigging. It was long a matter of considerable moment to devise means fur sim plifying the mode of manufacture, which re quires great accuracy, and thus diminishing the cost. In 1781 a large manufactory was established at Southampton by Mr. Taylor, who had secured a patent for an improved method of making sheaves, and who further adapted machinery for cutting the timber and shaping the shells of the blocks. Mr. Taylor for some time supplied all the blocks re quired for the navy ; but shortly after the ex piration of his patent machinery was intro duced into the dock-yard at Portsmouth, and the government undertook the manufacture, with the double object of economy, and of being independent of any individual for the supply of an article of first necessity for the equipment of ships.
• About this time (1801) the late Sir M. I. Brunel succeeded in completing a perfect working model for constructing both the shells and sheaves of blocks. This model being submitted to the inspection of the Lords of the Admiralty, the invention at once adopted by government, and the inventor was engaged to superintend the construction of the requisite machinery upon a scale suffi ciently large for making blocks to supply the whole naval service of the country. The com pletion of this machinery occupied nearly six years, and was not brought into full operation until September 1808, since which time it has been found to work without requiring any alteration. It is a truly beautiful combination of mechanism. It consists mainly of an assemblage of saws and lathes, forming an extensive series of machines all of which are set in motion by one steam-engine. By some of these the logs of elm from which the shells are to be formed are cut up into pieces of suitable dimensions; others bore the holes for the, pins or axles, and cut the mortices into which the sheaves arc to be placed ; others cut off the corners and complete the rounding and shaping of the shell by very ingenious arrange ments ; and another, the scoring-machine, cuts the grooves intended to receive the rope by which the block is to be suspended. An
other series of apparatus is provided for cut ting the lignurn-vitte of which the sheaves are mid° into slices, sawing them to a circular drape and cutting a round hole in the centre, fixing in the centro hole a metal cock, or ring, through which the axis is to pass, forming the groove in the edge of the sheave, and turning and polishing the iron pins for the axles. It is found that with this machinery ten men can perform the work that previously required one hundred and ten, and can easily produce 140,000 blocks per annum. Sir M. I. Brunel received 20,0001.from government as a reward for his ingenuity; yet it is said that the savings of four years, as compared with the cost of blocks made in the former manner, were suffi cient to defray this sum and the whole cost of erecting the buildings and machinery. So important has this mechanism been regarded, in a national point of view, that duplicate ma chines have been constructed in the Chatham dock-yard, to be used in case of accident to those at Portsmouth.
Ship's blocks for the mercantile navy arc still made by band, and improvements are frequently made therein.
Among many recent patents relating to ship's blocks, one by Mr. Stowe, of Bermuda, describes the use of a metal fork which contains the block, and which has a hole drilled in the lower part of each leg ; through this pair of holes is passed the spindle on which the spear revolves. Another patent, taken out by Capt. Chamier in 1849, relates to improvements in the strapping, the cheeks, and the sheaves. Instead of the ordinary rope strapping, a coil of strands of iron wire is used, coated or painted for preservation ; the cheeks are formed of two thin metallic sheets, one flat and one convex, filled up by soft metal between them ; the sheave is formed of three metal discs—the outer ones bent, and having their ends turned over to form the groove for the rope, while the centre one is kept straight.