Car lighting has passed through the same stages as house lighting, possibly more gradually, on account of the greater difficulties. The old low-roofed passenger cars were illuminated by candles about two inches in diameter, placed in racks along the sides of the car. With the advent of mineral oil, just before the Civil War, the candles gave place to oil lamps. Great difficulty was experienced in maintaining a steady flame, until the principle of the student lamp was adopted. The flame was shielded from the outside air by a chimney, and the central draft to the burner provided the air necessary, at the right point, to insure combustion. For more than fifteen years this method prevailed, and while the presence of oil lamps in wrecks contributed fuel to the flames, the proof that they were in any way the principal cause was lacking. Still, to eliminate this contributory feature, attempts were made to use ordinary coal gas, compressed in tanks on each car. This, however, proved unsatisfactory. In 1870 a system of compressed gas made from crude petroleum had been invented by Julius Pintsch, of Berlin, and by 1887 had been put into a number of cars on European railroads. The light was too dim to satisfy American conditions. It was only a question of time, however, for its proper and adequate development to our needs, when its use became general, on the perfection of the lamp and burner. For the last fifteen years electric lighting of various types has been in use on cars in an experimental way. While possessing advantages, perhaps, in safety, owing to low voltages and small quantity of current, its general use has not yet been entirely practicable, owing to the complications involved, either in generating and satisfactorily controlling the current upon the cars, or in supplying it at terminals through storage batteries.