CHAPTER XI

THE BANISHMENT OF NIGHT

Primitive torch and open lamp, p. 202--Tallow candle and perfected lamp, p. 205--Gas lighting, p. 207--The incandescent gas mantle, p. 208--Early gas mantles, p. 209--How the incandescent gas mantle is made, p. 211--The introduction of acetylene gas, p. 212--Chemistry of acetylene gas, p. 214--Practical gas-making, p. 215--The triumph of electricity, p. 218--Davy and the first electric light, p. 220--Helpful discoveries in electricity, p. 222--The Jablochkoff candle, p. 223--Defects of the Jablochkoff candle, p. 225--The improved arc light, p. 226--Edison and the incandescent lamp, p. 228--Difficulties encountered in finding the proper material for a practical filament, p. 230--"Parchmentized thread" filament, p. 233--The tungsten lamp, p. 234--The mercury-vapor light of Peter Cooper Hewitt, p. 236--Advantages and peculiarities of this light, p. 240.