The Eleventh Improvement

Consists in making the sheaves of ships' blocks in a different manner from what is usual, by which improvement the ropes will run easier, and the blocks will be less expensive to make -- and I accomplished it by placing a brass or other metal tube in the centre of the sheave, and then running molten lead, or other soft metal, into notches or groves between the tube and the sheave, so as that when the lead cools, the tube is prevented from starting from its position until entirely worn out.

. . .

Shipwreck and Collisions at Sea greatly prevented by Christophers' Patent Improvements in Naval Archtecture. With four plates.
London: J. Olliver, 59, Pall Mall; P. Richardson, 23, Cornhill. Liverpool: Deighton & Laughton. M.DCCC.L. 8vo, (4), 112 p, 4 pl.

Transcribed by Lars Bruzelius

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