the same arrangement the moment of the occurrence of some phenomenon. For if a tape be unwound automatically, as in the Morse instrument, it is easy so to arrange matters that every second’s beat of the pendulum records itself by a dot or short line on the tape, and that the observer can with a touch make (or break) contact at the instant of observation, and so a mark be made properly placed between two seconds’ marks—thus giving the precise time when the observation was made. Such applications, however, though exceedingly interesting to astronomers, are not among those in which the general public take chief interest. There was one occasion, however, when astronomical time-relations were connected in the most interesting manner with one of the greatest of all the marvels of telegraphy: I mean, when the _Great Eastern_ in mid-ocean was supplied regularly with Greenwich time, and this so perfectly (and therefore with such perfect indication of her place in the Atlantic), that when it was calculated from the time-signals that the buoy left in open ocean to mark the place of the cut cable had been reached, and the captain was coming on deck with several officers to look for it, the buoy announced its presence by thumping the side of the great ship. _THE PHONOGRAPH, OR VOICE-RECORDER._ In the preceding essay I have described the wonderful instrument called the telephone, which has recently become as widely known in this country as in America, the country of its first development. I propose now briefly to describe another instrument—the phonograph—which, though not a telegraphic instrument, is related in some degree to the telephone. In passing, I may remark that some, who as telegraphic specialists might be expected to know better, have described the phonograph as a telegraphic invention. A writer in the _Telegraphic Journal_, for instance, who had mistaken for mine a paper on the phonograph in one of our daily newspapers, denounced me (as the supposed author of that paper) for speaking of the possibility of crystallizing sound by means of this instrument; and then went on to speak of the mistake I (that is, said author) had made in leaving my own proper subject of study to speak of telegraphic instruments and to expatiate on the powers of electricity. In reality the phonograph has no relation to telegraphy whatever, and its powers do not in the slightest degree depend on electricity. If the case had been otherwise, it may be questioned whether the student of astronomy, or of any other department of science, should be considered incompetent of necessity to describe a telegraphic instrument, or to discuss the principles of telegraphic or electrical science. What should unquestionably be left to the specialist, is the description of the practical effect of details of instrumental construction, and the like—for only he who is in the habit of using special instruments or classes of instrument can