NEW WONDERS OF TELEGRAPHY.

Evening Star, Issue 10339, 12 June 1897, Page 2 (Supplement)

NEW WONDERS OF TELEGRAPHY.

~ 5 THREE THOUSAND WORDS IN A MINUTE. At a meeting Of the American Institute of Electrical Engineers in New York on 21st April, Albert Cushing Crehore, professor of physical science of Dartmouth College, exhibited an instrument designed to revolutionise telegraphy. "By the use," he said, "of the syncronograph 3,000 words a minute can easily be telegraphed, and what is, of course, equally important, cau as easily be received and recorded. A duplex line will carry 6,000 words a minute." \ In Chicago on 21st April Professor Crehore's collaborator in the invention of the syncronograph, Lieutenant George Owen Squier, United States Navy, was describing the remarkable machine to another branch of the same Institute. It may be here stated (remarks a New York correspondent of the ' San Francisco Chronicle') that these two gentleman, Crehore and Sqnier, invented the polarising photooronograph, with which the most successful experiments were made at the electrical laboratory of the United States Artillery School at Fortress Monroe. The photo-cronograph is a machine to measure the velocity of projectiles. The receiver of the syncronograph, that will receive 3,000 words a minute, is a development of the photo-cronograph. The rapidity of this receiver is illustrated by stating that as many as seven observations upon a projectile inside the bore of United States 32in breech-loading field rifles have been recorded in the first of its travel. Observations of a cannon ball moving with such tremendous velooity, as near together as 1 Jin, have been obtained. These observations correspond in time to less than a thousandth of a second, or they bear about the same relation toaseoond as a second does to twenty minutes. In measuring and recording time, as applied to gunnery, the projectile itself operates on the transmitter circuit, making and breaking the oirouit by passing through screens. It is perfectly plain that if the screens are placed acoording to a oode, a message could be transmitted to the receiving machine by a projectile in its flight. He uses the alternating current, impressing upon it the characters of the telegraphic code without affecting its regular operation. He employs wave lengths and half-wave lengths in alternating currents, of which there are 140 complete waves per second. By this plan it iB possible to use the ordinary continental telegraph code of dashes and dots—the dash being indicated when two successive waves (a positive and a j. negative one) are omitted by keeping the key open, and the dot when a single halfwave is left out.