In 1583, an inventor, whose name does not appear, proposed, as one out of twenty inventions:—“An engine for cleansing or taking away of any shelves or shallow places in the river of Thames, or any such river; the same device may serve for cleansing of ditches about cities or towns, ponds, or any such like standing waters.”—Rara Mathematica, edited by J. O. Halliwell, F.R.S., &c. 8vo. 1841.
John Gilbert obtained a patent, dated 16th July, 1618, for a water plough, for the taking up of sands or banks out of the river Thames or other places. And the same John Gilbert, with James Freese, obtained a patent, dated 8th July, 1631, for engines or instruments, called water ploughs, for the taking up of sands, gravel, shelves, and banks out of the Thames and other havens. Also Symon Hill, on the 30th May, 1633, patented his invention for taking away of beds of sand and gravel from rivers.
93.
An Engine whereby one man may take out of the water a Ship of 500. Tun, so that it may be calked, trimmed and repaired without need of the usual way of stocks, and as easily let it down again.
[A Ship-raising Engine.] We find in Besson’s admirably illustrated folio work on Instruments and Machines, 1578, many means delineated for raising vessels; for taking them bodily out of the water; or, for laying them high and dry on shore for repairs, as in plates 55, 56, and 58. All such methods are naturally, however, not only very rude and imperfect, but are at best only applicable for small craft.
In 1636, Sir John Christopher Van Berg, Moravian Knight, dispossessed of all his property “by the devouring wars in Germany,” patented eleven inventions; the fifth being—“An assured way how the very greatest ship may be drawn up again, though it be sunk 80 fathoms deep.”
94.
A little Engine portable in ones Pocket, which placed to any door, without any noise, but one crack, openeth any door or gate.
[A Pocket Engine to open any door.] Doppelmayr gives an account of the screw-jack invented by Leonard Danner in 1550. It must have been well known in the following century, and we can readily understand how the principle of its action may have occurred to the Marquis for application to a pocket instrument that would exactly accord with his statement.
Bishop Wilkins, in his “Mathematical Magick,” 1648, treating on the employment of multiplied wheels, refers to Ramelli, Figure 160, observing:—“Hither also should be referred the force of racks, which serve for bending of the strongest bows, as also that little pocket engine wherewith a man may break or wrench open any door, together with divers the like instruments in common use.”—Chap. 13, pages 91, 92.