The Century of Inventions of the Marquis of Worcester / from the Original MS., with Historical and Explanatory Notes and a Biographical Memoir

by Marquis of Edward Somerset Worcester

No. XCII.

A screw, made like a water-screw, but the bottom made of iron-plate spadewise, which, at the side of a boat, emptieth the mud of a pond, or raiseth gravel.

NOTE.

The Archimedean screw, though hitherto only applied to the raising of water, appears to be equally applicable to many other purposes; as the procuring of sand from pits, taking dry goods of small dimensions from carts or barges, clearing rivers, &c. though in that case it will be necessary to make the lower end of the machine in a conical form, gradually increasing the size of the orifice from the point to its upper extremity, in order to prevent the materials from clogging the screw, which would otherwise occur.

The dredging machine worked by a steam-engine, and employed in the Thames for a similar purpose, is well known.