Ocean Telegraphy

He (the ocean telegrapli operator), saya tbe Boston Herald, taps the "koy" ; as in a land telegrapli, onlyit is a doublé ■ key. It has two levers and knobs matead i of one. The alphabet used is substantially like the Morse alphabet ; that is, the different letters are representad bv a cornbination of dashes and dote, For infitanoe, suppose you want k write the word "boy." It would read like this : __, . . -! _. " B is one dash and ihree dots ; O, three dasheK ; and Y, one dash, and one dot, and three dashes. Now, in the land telegraph, tho dashes and tlie dots would appear on the ' strip of paper at the other end of the line, whioh is unwound from a cylinder and perforated by a pin at the errd of the bar or armatnre. If the operator could ; read by sound, we would dispense with ■ the strip of paper, and read the message I by the "click" of the arniature as it is j pulled down and let go by the electrie niagnet. The cable operator, howeyer, has neither of these advantages. There is j no paper to perfórate, no " cliek" of the armature, no armature to " click." The j message is read by mean of a moving flash of light upon a polished scale produced by the " deflection" of a very small mirror, which is placed within a " mirror ! {alvauometer," which is a small brass j (ylinder two or three inches in diameter, ; shaped liko a spool or bobbin, composed I of several huudred tums of small wire ! I woiiiid with silk to keep the metal from cominer in contact. It is wound or coiled exaeüy likc a bundie of new rope, a small hole being left in the miildle about tho i size of a common wooden pencil. In I the center of this is suspended a very i thin, delicate mirror about as largo as a kernel of corn, with a correspondmgly ', small magnet rigidly attached to the j back of it. The whole weighs but a j tle more than a grain, and is suspended by a single fibre of silk much smaller than a human hair, and almost invisible. ; A narrow horizontal seale is placed within a darkened box two or tbree feet i in front of the mirror, a narro-w slit being j cut in the center of the scale to allow a i ray of light to shine upon the mirror from a lamp placed behind said scale, the j little mirror in turn reflecting the light baek upon the scale. This spot of light upon the scale is the index by which all messages are read. The angle tlu-ough which the ray moves is doublé that versed by the inirror ïtself ; and ït is i therefore, really equivalent to au index f six f eet in length without weieht. To the casual observer there is ing but a thin ray of light, darting to the ; right and left with irregular rapidity ; j but to the trained eye of the operator every flash is replete with inteiiigence. Thus the word," boy," ah-eady alluded to, would be read in this way : One flash ! to the right and three to the left is B. Three flashes to the right is O. One to j the right, one to the left, and two more I to the right is Y, and so on. Long and constant practice makes the operators wonclerfuUy expert in their profession, and enables them to read from the inirror as readily and as accurately as from a newspaper.