WE have now seen the Edison lighting system given a complete, convincing demonstration in Paris, London, and New York; and have noted steps taken for its introduction elsewhere on both sides of the Atlantic. The Paris plant, like that at the Crystal Palace, was a temporary exhibit. The London plant was less temporary, but not permanent, supplying before it was torn out no fewer than three thousand lamps in hotels, churches, stores, and dwellings in the vicinity of Holborn Viaduct. There Messrs. Johnson and Hammer put into practice many of the ideas now standard in the art, and secured much useful data for the work in New York, of which the story has just been told. As a matter of fact the first Edison commercial station to be operated in this country was that at Appleton, Wisconsin, but its only serious claim to notice is that it was the initial one of the system driven by water-power. It went into service August 15, 1882, about three weeks before the Pearl Street station. It consisted of one small dynamo of a capacity of two hundred and eighty lights of 10 c.p. each, and was housed in an unpretentious wooden shed. The dynamo-electric machine, though small, was robust, for under all the varying speeds of water-power, and the vicissitudes of the plant to which it, belonged, it continued in active use until 1899--seventeen years. Edison was from the first deeply impressed with the possibilities of water-power, and, as this incident shows, was prompt to seize such a very early opportunity. But his attention was in reality concentrated closely on the supply of great centres of population, a task which he then felt might well occupy his lifetime; and except in regard to furnishing isolated plants he did not pursue further the development of hydro-electric stations. That was left to others, and to the application of the alternating current, which has enabled engineers to harness remote powers, and, within thoroughly economical limits, transmit thousands of horse-power as much as two hundred miles at pressures of 80,000 and 100,000 volts. Owing to his insistence on low pressure, direct current for use in densely populated districts, as the only safe and truly universal, profitable way of delivering electrical energy to the consumers, Edison has been frequently spoken of as an opponent of the alternating current. This does him an injustice. At the time a measure was before the Virginia legislature, in 1890, to limit the permissible pressures of current so as to render it safe, he said: "You want to allow high pressure wherever the conditions are such that by no possible accident could that pressure get into the houses of the consumers; you want to give them all the latitude you can." In explaining this he added: "Suppose you want to take the falls down at Richmond, and want to put up a water-power? Why, if we erect a station at the falls, it is a great economy to get it up to the city. By digging