'TELEPHONIC TIME SIGNALS, In our daily issue there appears an advertisement of the Time Signals which the China and Japan Telephone Company propose to distribute to their subscsi Shanghai, Woe lately paid a Telephone Exchange on the Bund, where the working of the time-signals was explained to us by Mr, Bishop. "It. is 40 Ingenious and interesting that we describe the process for the benefit ut our read Tt appears that the telephone and. time-ball wires from Sicawei Obs Semaphore Station on the ass, en route, through the Telephone xchange, and are there connected with complete and special apparatus which enables the manager to judge for faction and the security of the public of the state of the lines and instruments any moment of the day, and to watch the indications given by Ue telephone and test currents sent through from Sicawei to the Time Ball, These precautions are necessary in view of the fact that the Timo Ball carmot be allowed any experimental falls, No latitude is allowed as in the case of ordinary tolegeaph ur telephone work, It must be in perfect working order at one particular second of the day, or be useless, or worse than useless, for' that next twenty-four hours. yughout the Settlement, it must be done without in the least interfering with the Observatory lines; and this problem has boon solved in the following simple though ingenious manner, The current oont from the Observatory at Sicawei which drops the ball, in passing through the Exchange gives a visual audible signal by dropping o small shutter, which follo with smart click. Advantage is taken of this utter dropping to distribute time.
nals, thus:—A big I2-inch gong la made fast to one of the dvore in the exchange room, which aeryes as a sounding board. Above this gong a hammer, working on a pivot, is auspouded by a amall electro magnet, which is, through connected. with a local battery, which is put into action automatically when the nutter is dropped by the noon signal from Sicawei Observatory. The noon signal therefore first drops the shutter, the shutter connects the battery, the battery actuated the electro-magnet, which rolexsos the hammer, which them strikes a loud blow he gong. So far al fectly plain 1 remains the taal tributing the al blow to as many subscribers as ro-quire it. 'This is accomplished in the following beautiful and delicate mau About " foot beneath the gong, and in no possible manner connected with the apparatus we have just described, is fixed a multiple carbon microphone' and an induction coil, The secondary wire of this cull is connected, one end to the earth and the other to a brass plate with numerous huies, At 6 minutes to 12 the Observatory funds a " Hoist the Ball" signal. As soon as this las been acknowledged the operator commences con necting all the subscribers who want the signal, with the brass-plate, by putting the various wire pluge in ite holes, At nyon the current from Sisawei drops the shutter, and the hammer strikes tue Its loud vibrations are communi-ted through the door and the air to the microphone, causing it to vibrate in atrict harmony therewith; and thus the microphone, by means of the induction coil, sends the exact note of the gong through each line connected with it, the time required to do this has be-n measured as uc: urately as is necessary, and found to be within two and three fifths of a second, So that such subscriber listening at his telephone hears the gong sound that amount of time slow, but as this is a constant error daily it ig of no. importance. A few seconde after the gong hasbeen struck the operator discunnects the wires from the induction coil and the business of the Exchange pursues its ordinary cou What strikes the uninitiated observer a8
Text read from the printed page and cleaned; old type leaves the occasional error.