Much apprehension was at first excited in the neighborhood of the companies' works by the enormous metal tanks, or reservoirs, until, as is related, an Englishman, named Clegg, one day went up to one of these huge gasometers, drove a hole through the side, and applied a lighted candle to the aperture. The escaping gas burned in a steady jet, as from a burner, but did not explode. At the opening of the siege of Paris, General Trochu was alarmed at the possibility of one of these gasometers in the suburbs being exploded by a German shell and destroying the ramparts in its vicinity; the Conseil de Défense, having communicated these apprehensions to the gas company, were assured by the latter that the reservoirs would not explode, even though pierced by a projectile. This statement was soon verified; at the works at Ivry, one of the enemy's shells fell through one of the iron _cloches_,--a long sheaf of fire rose in the air, and was extinguished within a few minutes. At La Villette, a shell burst inside the tank, but the gas escaped without any further damage. It was the latter usine that furnished the means of inflating the balloons that, for so long a time, constituted the city's only method of communication with the outside world. If the municipality was somewhat slow in adopting the use of gas for its streets, it claims to be the first to have introduced that of electricity. This new method of illumination appeared in 1876, and in the following year the Avenue de l'Opéra was lit up by the Jablochkoff system. In England, the use of electricity for lighting public streets and dwellings was inaugurated in the town of Godalming in 1881; and in America, in New York, in 1882. The Place du Carrousel followed the Avenue de l'Opéra, using sixteen Mersanne lights; experiments were made in the Parc Monceau with fourteen arc lights, and in the Parc des Buttes-Chaumont with fifty arc lights and seventy-nine incandescent. The tragic burning of the Opéra-Comique, in May, 1887, gave a great impulse to the adoption of the new method in preference to the use of gas, and the city north of the Seine was divided into five _secteurs_, each furnished by its own electrical company. This method still prevails, the number of secteurs having been increased to seven, one for the left bank of the river, and the different companies hold their concessions for the space of eighteen years. The unit of measurement is the _hectowatt-heure_, the price of which ranges from ten to fifteen centimes, whilst in other cities, according to statistics of November, 1897, it ranged from five to seven centimes in Brussels, from six to seven in London, and at about seven and a half in Berlin. [Illustration: AN "IMMORTAL" AT THE ENTRANCE TO THE INSTITUT DE FRANCE. After a drawing by Émile Bayard.]