Page:Popular Science Monthly Volume 71.djvu/31

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across the North River at about Fort Lee. It only worked a few days when it was dragged out of place by a ship's anchor. The first iron-armored cable was made by S. C. Bishop in 1852, and was used across the North River, above Cold Spring. This cable was of No. 14 copper wire with an insulation the size of No. 0, protected by jute and armored with iron wire about No. 8.

Submarine telephone cables were used in 1879 by several companies in crossing rivers and bays, notably in Chicago and Milwaukee, and Patterson telephone cables were placed in the Washington Street tunnel crossing under the Chicago River, in 1879, as previously stated. But probably the first telephone cables that formed a part of a regular underground system were laid in Pittsburg in 1881, by Henry Metzger. Three lead-covered cables were laid on Fifth Avenue between the exchange and a distributing pole, about a thousand feet distant. The cables were composed of 50 single conductors of No. 26 copper wire, and were placed in a wooden box, 6 x 8 inches, made of one-inch plank, that was then filled with asphalt and laid inside the curb below the frost line. No manholes were used, but connecting wires were spliced with a T-joint. In June, 1882, Mr, Metzger laid eight more Patterson cables underground, the longest being 2,200 feet in length, composed of No. 18 B. & S. single copper wires. These cables gave good service for a number of years. That same year, 1882, the New England Telephone and Telegraph Company laid two Patterson 50-pair cables in Boston, for metallic circuit service. The lead-covered cables were drawn in iron pipes laid in cement. One cable was 1,200 feet and the other 1,485 feet in length; both were composed of No. 22 wire, cotton covered. One was laid in Pearl Street in October, the other in Franklin Street in November, 1882.

On May 20, 1882, Professor Chas. R. Cross, in considering the various electrical problems involved in the introduction of underground telephone cables wrote:

In the first place it should be remembered that the number of wires in foreign cities is probably not more than one fifth as great as in American cities of equal size. Thus in Bruges, Belgium, a city of 50,000 inhabitants, there is but one telegraph office, that at the railway station; in Ghent, with 120,000 inhabitants, there is but one telegraph office; in Antwerp, with its enormous commerce, there are but two, one being at the railway station; and in Brussels proper, only one office except at the railroad stations.

In London and Paris almost all messages are sent from the outlying offices to the central telegraph office oy means of pneumatic tubes, and the telegraphic despatches sent from there. From these facts it will be seen that the absolute number of underground wires in foreign cities is much less than is popularly supposed. Contrast in this respect Boston and suburbs, with 377,000 inhabitants and forty-nine telegraph offices, and Brussels and suburbs with 315,000 inhabitants, and eight or at most ten offices.

In April, 1882, thirty-eight sections of a lead-encased telephone cable were laid underground between the two tracks of the Boston & Providence Railroad extending from the depot in Attleboro to West