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. LIV.

How to make a water-screw tight, and yet transparent, and free from breaking; but so clear, that one may palpably see the water, or any heavy thing, how and why it is mounted by turning.

NOTE.

This may be readily effected either by making a coarse screw in the usual manner, and covering it with horn, or by fitting a spiral tube of glass on a wooden cylinder, and filling up the interstices with wax or any hard cement so as to project beyond the glass tube: this appears the most eligible method, though the former is the most economical.

M. A. Rochon has likewise proposed a most ingenious substitute for the use of horn in the construction of the Archimedean screw, and other hydraulic instruments. It is formed (like the safety lamp of Sir H. Davy) of a coarse wire gauze which, on being immersed in pure fish-glue or size, forms when varnished a cheap and durable substitute for the use of glass.