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Page:Popular Science Monthly Volume 70.djvu/241

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the operator, who cut off the battery by turning a switch and then inserted a plug in the line socket and received the call. The companion cord was then removed from the ground plate and inserted in the socket of the line called for. Mr. Doolittle states that on several PSM V70 D241 Doolittle switchboard connections.pngFig. 17 occasions he saw the operator take care of four calls at the same time by holding two telephones in the fingers of each hand, that is, the operator had to talk and then listen into four separate telephones; in other words, using both ears as well as both hands. Incidentally it may be mentioned that Mr. Doolittle claims that it was on this board that the first female telephone operator was employed. A glance at the illustration shows that the cylindrical wooden weights suspended on the plug cords were about an inch in diameter and a foot in length, with a brass pulley attached to the top of each. These long weights were employed at first in anticipation that their length would prevent the cords from swinging and tangling, but later were displaced by smaller but heavier lead weights.

According to a local paper the switchboard erected in Philadelphia, in December, 1878, consisted of

a walnut frame and braced strips of brass punctured with holes, into which wires are fitted to make the necessary connections. Behind this all the wires converging in the office concentrate. The board accommodates 400 different lines.

In October, 1878, the parent 'Bell Telephone Company' issued a circular describing a form of brass strip switchboard 'adapted for six circuits.' On February 20, 1879, a circular was issued describing a switchboard which could be supplied at

from 50 cents to $1 per circuit, according to the number of circuits. The dimensions of this switchboard for from 50 to 200 circuits are 6 feet long by about 3 feet wide.

Switchboard tap-bells were listed at $2.50 each; subscriber's hook district bells, $3.25 each; spring keys, 75 cents each; lightning arresters, 37 cents per circuit. It was stated that "the following plan it is