Page:Popular Science Monthly Volume 52.djvu/754

732 required becomes as great as can be insulated with certainty in the present state of the art, the distance of transmission is increased to the utmost limits attainable in practice. Until some more perfect means for confining the current is devised, greater results can not be reached. With our present knowledge of insulating materials, and our methods of applying them, it would be practically impossible to transmit energy over distances as great as from New York to Niagara, but it does not follow that the accomplishment of this result will never be witnessed; it is a possibility of the future, that may not come for a century or more, or may be realized within the next few years.

Although the achievement of such stupendous results as the transmission of power over several hundred miles is not within our present reach, it is possible to bridge distances of twenty or thirty miles, and the accomplishment of this much has been considered entirely practicable for several years. It was on this account that the Niagara power plant was started, the object being to supply the city of Buffalo and other places within a radius of twenty-five or thirty miles. This undertaking, owing to the magnitude of the power available, has attracted world-wide attention, and is probably regarded by the vast majority of people as the only work of any importance in this line that has been attempted. This, however, is far from being true; it is the largest, and will undoubtedly always remain such, since the source of energy is practically unlimited, but there are several other very large installations, and in some of these the distance of transmission from a mile or so up to thirty-five miles, place being nearly double that distance.

A fair idea of the extent to which this branch of the electrical industry has been developed may be gained from a consideration of the fact that one manufacturing concern alone has sold over two hundred thousand horse power of machinery for this purpose within the last four or five years, their sales for 1896 being over seventy-five thousand horse power. The great increase in the business during the past year, in the face of a general stagnation in all other lines of industry, is a very clear indication that what has been done in the past has been entirely successful—so much so as to inspire an amount of confidence sufficient to overcome the apathy or unwillingness to embark in new undertakings so manifest in all other lines of business.

The total number of water-power transmission plants in successful operation in the United States in addition to the Niagara installation is over two hundred. The amount of power transmitted ranges from less than one hundred horse power up to twelve thousand, and the distance of transmission from a mile or so up to thirty-five miles.