Page:Popular Science Monthly Volume 22.djvu/349

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From London to the country:[1] For the 10 a. m. signal, 12 to £17 $60 to $85. For the 1 p. m. signal, £27 to £32 $135 to $160. In London: For the hourly signal within a radius of two miles from the General Post-Office, £15 $75. But if the person desiring the signal is off the line of the telegraph, he must pay, besides a stipulated rental, an additional sum for the use of the wire which the department is compelled to put up specially for him. The rental is in all cases payable yearly in advance.

In 1880 there were one hundred subscribers to the system, of whom nineteen were in London, and eighty-one scattered through England, with a few in Scotland and Ireland.

Besides this general automatic distribution of the time-signals, a considerable distribution of the 10 a. m. signal goes on by hand. At that instant the chronopher makes a sound which an operator sits ready to catch by ear. Upon hearing it he immediately dispatches a signal by the ordinary telegraphic instrument, and this signal is received at six hundred or more places, which again serve as distributing points for more distant places. These are usually railway or post offices in towns not supplied by the chronopher, which by virtue of authority become the regulators of the clocks of the surrounding district.

The wire from the observatory to London Bridge carries signals hourly from the mean solar standard to a clock at the station of the Southeastern Railway, which by changing connections sends Greenwich time to different stations along the line as may be required. For this service the Southeastern Railway gives the observatory the use of its wire daily, for a few minutes, at 1 p. m. At this time the current from the observatory drops the time-ball at Deal, which was erected in 1855, to give time to the shipping in the Downs, and is the only official coast time-signal. The ball in falling sends a "return" signal to the observatory. The record shows that about once in two months high wind prevents the raising of the ball, about once in six weeks it fails to fall on account of some fault in the electric connections, and about once a year it drops out of time. Under such circumstances it is dropped correctly at 2 p. m.

By special arrangement with the observatory a few London jewelers receive the hourly Greenwich current on private wires. This they use for the correction of their own time-keepers and in some cases for distribution. Prominent among these are the Messrs. Barraud & Lund, of Cornhill, who have patented a method for the synchronization of clocks. Their plan is put forward as a simple and effectual means of setting any number of ordinary clocks to the same standard time. All attempts to control clocks have been set aside as impracti-

  1. Difference in charge for the same signal depends on the length of wire which the department is compelled to put up specially for the subscriber. The one o'clock signal is more expensive, because the wires are busier with telegraph duties at that hour than at 10 a. m.