MISCELLANEOUS. 329 



Sir Humphrey Davy found, that the images of 

 small objects produced by means of the solar mi- 

 croscope, may be copied without difficulty on 

 prepared paper : the best proportion was one 

 part of nitrate to about ten of water. This is 

 sufficient to enable the paper to become tinged, 

 without hurting its texture. 



Artificial Fire-Works. 



Artificial fire-works are of two kinds those 

 made of gunpowder, nitre, and other inflammable 

 substances and filings of the metals, camphor, &c.; 

 and those produced by hydrogen or inflammable air. 



Those made with gunpowder are well known, 

 and are called rockets, fire-wheels, tourbillons, &c. 



Of these, the most usual are rockets. They are 

 made by ramming into strong cylindrical paper cases 

 put into wooden moulds, like small hollow columns, 

 powdered gunpowder, or the ingredients of which it 

 is composed; viz. saltpetre, sulphur, and charcoal, 

 very dry. 



If you would represent a fiery rain falling from 

 the rocket, mix among your charge a composition 

 of powdered glass, filings of iron, and saw dust ; this 

 shower is called the peacock's tail, on account of the 

 various colours that appear in it. Camphor mixed 

 with the charge produces white or pale fire; resin 

 a reddish colour; sulphur a blue ; sal ammoniac a 

 green ; antimony a reddish yellow ; ivory shavings 

 a silvery white, pitch a deep or dark coloured fire, 

 and steel filings beautiful corruscations and sparks. 



Sticks are fastened to the rockets by which they 

 are projected into the air, after they have been 

 lighted ; the charge, burning with great intensity 

 at one end, acts upon the air, which, in its turn, 



