BY J. W, SUTTON. XIX. 



appreciate for the first time the comforts of a white light ; 

 and thus the oil lamps replaced in a great measure the 

 candle. But it was not until LS48, when Dr. Lyon 

 Playfair called attention to the oozing of petroleum from 

 the coal seams, then with the discovery of mineral oils 

 in America and Russia, which brought forth the birth of present 

 kerosene oil lamps, which has steadily improved until it 

 has now about reached the climax of perfection. Prior to the 

 introduction of electric lighting, improvements in gas and gas- 

 burning were few and far between, and it was only by Act of 

 Parliament that gas companies were compelled to supply 

 consumers with an article of standard light and quality, in fact, 

 gas companies the world over did just what they pleased ; but 

 within the past sixteen years a great change has come over the 

 scene, electric light companies having given them a shock that 

 has awakened them into a new life and activity, meaning better 

 quality of gas, new and improved burners, and cheaper rates; 

 and one of the chief factors in enabling them to hold their own 

 is that beautiful invention now so familiar to us all, the Welsbach 

 incandescent mantle. This has been greatly improved since its 

 introduction about eight years ago, thorium being the metal 

 now ussd in its construction. Still, for a perfect light both for 

 health and comfort, the electric incandescent light stands alone ; 

 it takes nothing from the air and gives nothing to it, excepting 

 a small quantity of heat — less than any other known illuminant ; 

 it costs less to install, and if properly done is the safest. If the 

 cost could b9 brought down to that of gas, as burnt in the 

 Welsbach burners, it would be universally used. This brings us 

 now to the last and latest rival in artificial lighting, viz., 

 Acetylene. It is now some seventy years past since Edmond 

 Davey, a relation of the great Sir Humphv'v, while ex- 

 perimenting in the process of the manufacture cf sodium and 

 potassium, noticed that a black residuum was at times formed 

 in the retort, which, practically had the same power of 

 decomposing water as potassium, only that the gas evolved by 

 the decomposition was, instead of being hydrogen, a compound 

 of that element with carbon. The proportion in which these 

 two elements united diftered from the composition of any 

 hydrocarbon then known. The material so formed in the retort 

 being a compound of carbon and potassium, which we know 

 now as potassic carbide, while the new hydrocarbon then given 



