The sheaves are generally made of lignum-vitæ; and the first operation is performed by a circular-saw, which cuts the wood into pieces of a proper thickness. By a second machine the holes for the pins are bored, and they are formed into perfect circles by means of a crown-saw. The third, called the coaking-machine, is an admirable specimen of mechanical ingenuity. By its operation, a small cutter drills out round the pin-hole--to a certain depth from the flat surface of the sheave--three semicircular grooves, for the reception of the metal coak, or bush, which sustains the friction of the pin. So truly are those grooves formed, that the slight tap of a hammer is sufficient to fix the coak in its place. The fourth operation consists in casting the coaks. By a fifth, after being fitted in the grooves, holes are drilled in the coaks, for the reception of the pins which fasten them to the sheaves; and by a sixth the pins are rivetted. By the seventh operation, the central hole in the coak for the pin, on which the sheave turns, is drilled out. By the eighth, the groove for the rope is turned round the circumference of the sheave, and its sides polished. In the ninth, the iron pins, on which the sheaves revolve, are cast, turned, and polished; and on their being inserted, the block is complete and ready for use. [Illustration: VIEW FROM THE SALUTING PLATFORM, PORTSMOUTH.] PORTSMOUTH. VIEW FROM THE SALUTING PLATFORM. The correctness of this view will be immediately recognised by every person in the least acquainted with Portsmouth. The platform, from which it is taken, forms the grand promenade of the inhabitants, and is usually the first place visited by strangers, on account of the prospect which is thence obtained. Immediately in front of the engraving is seen the northern extremity of the platform, on which are two soldiers, who seem indulging themselves with a leisurely inhalation of the fresh breeze from the water, after having liberally expended a portion of their own breath in sounding their bugles at parade. Beyond the platform, the most conspicuous object is the Government Semaphore, with three flags displayed as a signal; and to the left, the landing-place called the King's Stairs. Beyond the old round tower is seen the flag-ship of the Port Admiral; and, between her and the gun-brig which is running in, a distant view is obtained of the Town Hall of Gosport.