Those who are curious in such matters, may see more at large in Dr. W. Hooper’s Rational Recreations, ed. 1794, 8vo. different methods of writing in cipher, commencing at p. 143, of 1st Vol.--thus:-- To communicate intelligence by a pack of piquet cards.--The musical dial.--The corresponding spaces.--The musical cipher.--Rules for deciphering.--Example of a cipher written in arbitrary characters, and the words separate from each other.--Visual correspondence; and, Correspondence by bells. 44. To make a Key of a Chamber door, which to your sight hath its Wards and Rose-pipe but Paper-thick, and yet at pleasure in a minute of an hour shall become a perfect Pistol, capable to shoot through a Brest-plate commonly of Carabine-proof, with Prime, Powder and Firelock, undiscoverable in a strangers hand. [_A Key-Pistol._] This mere piece of ingenuity, so pleasing to certain mechanics in working out mechanical trinkets, might be effected by causing the removal of the key handle to expose a sufficiently strong pistol barrel, while the “rose pipe but paper thick” would answer to receive, and perform the office of retaining the key handle securely, by which to hold it while firing this key-pistol. The next part of the contrivance would be, to make the “wards” serve to conceal the pistol pan, cock, &c. The description is well calculated to mislead the reader, under the impression that the barrel itself is “but paper-thick.” 45. How to light a Fire and a Candle at what hour of the night one awaketh, without rising or putting ones hand out of the bed. And the same thing[7] becomes[8] a serviceable Pistol at pleasure; yet by a stranger, not knowing the secret, seemeth but a dexterous Tinder-box. Footnotes [7] to be a. P. [8] becomes to be. [_A most conceited Tinder-box._] The following note from “Humane Industry,” 1661, appears highly suggestive of such an instrument, although the Marquis’s invention is more elaborate. “Andrew Alciat the great Civilian of France, had a kind of Clock in his chamber, that should awake him at any hour of the night that he determined, and when it struck the determined hour, it struck fire likewise out of a flint, which fell among tinder, to light him a candle: it was the invention of one Caravagio of Sienna in Italy.” 46. How to make an artificial Bird to fly which way and as long as one pleaseth, by or against the wind, sometimes chirping, other times hovering, still tending the way it is designed for. [_An artificial Bird._] The third article in his list of a portion of his inventions supplies a different reading, thus: “By this (his ‘quint-essence of motion’) I can make an artificial bird to fly which way, and as long as I please.” [Appendix A.]