The pistol tinder-box may readily be made to perform the whole of what is here described. A bell rope attached to the trigger will suffice to elicit fire, which, communicating with a quick-match or fusee, will quickly ignite and produce the required light. If the fire is previously prepared with wood or some other combustible material, and a small quantity of inflammable spirits sprinkled over it, the slightest spark will throw the whole into a blaze. For the latter qualification mentioned by the noble author, a pistol barrel may easily be secreted under the tinder. The inflammable air-lamp contrived by Volta possesses similar properties: a stream of hydrogen gas being inflamed by the spark from an electrophorus.--Vide _Brande's Manual of Chemistry_, vol. i. p. 240. No. XLVI. 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. NOTE. In the year 1810, two birds were exhibited at the museum of the late Mr. Merlin; these performed nearly all the evolutions described by the Author: with this exception, however, that they were supported by fine wires; and a similar bird was exhibited in London in the year 1786.--Vide _77th Art. in the Century_. No. XLVII. To make a ball of any metal, which, thrown into a pool or pail of water, shall presently rise from the bottom, and constantly show, by the superficies of the water, the hour of the day or night, never rising more out of the water than just to the minute it showeth of each quarter of the hour; and if by force kept under water, yet the time is not lost, but recovered as soon as it is permitted to rise to the surface of the water. NOTE. A metal ball graduated on the surface, in the same manner as the index stem to an hydrometer, with a balance to preserve its equilibrium, must first be exhausted of air, which being effected, the water may be allowed to enter by a small aperture, and it will gradually sink till the vessel is filled: this, if the ball is about 12 inches in diameter and the aperture of a proportionate size, will not take place in less than twelve hours. No. XLVIII. A screwed ascent, instead of stairs, with fit landing places to the best chambers of each story, with back stairs within the _noel_ of it, convenient for servants to pass up and down to the inward rooms of them, unseen and private. NOTE.