for writing, and in making the charge only the size of the written sheet has to be taken into consideration. If this machine is all that it promises, Mr. Sawyer deserves immortality, and may probably receive a statue.

But much more than this is announced from America. Says Sir W. Thomson: "In the United States telegraphic department, I saw and heard Elisha Gray's splendidly worked out electric Telephone (sound from a distance), actually sounding four messages simultaneously on the Morse code, and clearly capable of doing yet four times as many with very moderate improvements of detail; and I saw Edison's automatic telegraph delivering 1015 words in fifty-seven seconds; and this done by the long-neglected electro-chemical method of Bain, long ago condemned in England to the helot-work of recording from a relay, and then turned adrift as needlessly delicate for that. In the Canadian department I heard, 'To be or not to be . . . there's the rub,' through an electric wire; but scorning monosyllables, the electric articulation rose to higher flights, and gave me passages taken at random from the New York newspapers-'S. S. Cox has arrived '-(I failed to make out the S. S. Cox); 'The City of New York;' 'Senator Morton;' 'The Senate has resolved to print a thousand extra copies;' 'The Americans in London have resolved to celebrate the coming Fourth of July.' All this my own ears heard spoken to me with unmistakable distinctness, by the thin circular disc armature of just such another little electro-magnet as this which I hold in my hand. The words were sounded, with a clear and loud voice, by my colleague, Professor Watson, at the far end of the line, holding his mouth close to a stretched membrane, carrying a little piece of soft iron, which was thus made to perform in the neighbourhood of an electro-magnet in circuit with the linemotions, proportional to the sonorific motions of the air. This, the greatest by far of all the marvels of the electric telegraph, is due to a young countryman of our own, Mr. Graham Bell, of Edinburgh, Montreal, and Boston, now a naturalized citizen of the United States. Who cannot but admire the hardihood of invention which devised such very slight means to realize the mathematical conception that, if electricity is to convey all the delicacies of quality which distinguish articulate speech, the strength of its current must vary continuously, and, as nearly as may be, in simple pro

portion to the velocity of a particle of air engaged in constituting sound?"

The Private Telegraph is becoming a necessity of every large public or private establishment having separate places of business. All the Government offices possess them. The different stations of the Fire Brigade are thus bound together; and the police-stations are similarly connected. At the time of the great fire in Tooley Street, on which occasion an excited and densely-packed crowd completely prevented the passing of any messenger through it, these telegraphs did immense service in enabling the authorities to hold in their hand the means of instant communication with distant divisional station-houses. In case of a serious riot it would be invaluable, as the wires could not be cut unless entrances to the private houses over which they passed were first obtained. M. Reuter has not been slow to see the advantages of these private telegraphs, as by their means he sends his telegrams directly into the editors' room of nearly every daily paper in London. The London and Westminster Bank is now in instant communication with all its branches, and the importance of this new agent in banking affairs has been followed by all the other houses. Even medical men have laid them down, or rather hung them up, between their private houses and consulting-rooms.

It is but due, however, to the enterprising North to say that the great merchants in its teeming cities have been the first to promote the further extension of the system, not only between house and house, but between town and town. Thus, nearly all the great manufacturers in the towns surrounding Manchester, possess private lines of telegraph with each other, and with the central capital around which they are grouped. In Liverpool and Glasgow, cables radiate in all directions, to the thickly populated neighbourhoods in their vicinity. Indeed, it may be said that these private telegraphs are almost as universal as the use of bells, and the time is not distant when, so far as great public and private establishments are concerned, everybody will be able to talk with everybody without going out of the house. We may state, in conclusion, that there is no possible connection between the wires of the two systems, except as the effect of mere accident. Thus, on one occasion, an uninsulated filament descending from one of the cables belonging to the old Private Telegraph Company, broke,

and fell across one of the naked wires of the District Telegraph Company. The consequence was a violent quarrel between the private sender of the message and the public receiver, on to whose wire the errant message had wandered. The rental from the private wires has increased from £26,425 in 1870, to £56,673 in 1875-76; the total number of miles of such wire being 5846, averaging about £9 14s. per mile.

THE WORKING OF THE POSTAL

TELEGRAPH.*

THE origin of the Postal Telegraph was a marvel of skill and contrivance, reflecting the greatest credit upon its designer, Mr. Scudamore,—for it might be termed a curiosity shop of engineering, scientific, and manual appliances, exhibiting that highest test of genius, "the infinite capacity for work."

The original building was in Telegraph Street, a small street opening out of the east side of Moorgate Street. Before the transfer of the telegraph from the Electric Company to the Post Office, the basement of the building was set apart for the engine-room, the messengers' waiting-room and dining-room, and the store-rooms. The first floor was set apart for the accountants' and engineers' offices; the second floor for the board-room, and the rooms of the Secretariat and the Intelligence Department. The second floor was mainly given up to the dining-room of the female and male staff. The third floor was devoted to the receipt and transmission of messages. space on each floor in the wings. entirely re-arranged by the Post Office.

There was some vacant
The building had to be

The whole of the second and third floors, with the exception of one small room, was given up to the work connected with the receipt and transmission of messages. On the first floor, offices for the engineering staff and the superintendent of the station were retained; but the board-room and the rooms of the Secretariat were co..verted into a dining-room and kitchen for the female staff,

* By A. Steinmetz.

66

and a sitting-room for the matron. On the ground floor, space was found for a sending-out" or delivery room, with a retiring-room for the female sending-out clerks; for the messengers' dining-room, and for the office of their inspectors; for the dining-rooms of the male staff; for a writing-room for the Press; for the surgery and consultingroom of the medical officers; for the Intelligence Department, and for the engineers' workshops. The basement was entirely appropriated to the engines, the batteries, and the

stores.

On the third floor of the building was what was called "The Provincial Gallery," or workshop of the establishment. The Central Station was mainly a "forwarding" or "transmitting" station, that is to say, its chief business consisted in the receipt of messages from one place for transmission to some other place. It did receive some messages for delivery within a certain area, and during the night it was open for the collection of messages from the public; but its work was mainly that of transmission.

The Provincial Gallery received and despatched messages

by means of wires and pneumatic tubes. What is a pneumatic tube? Any one may extemporize a pneumatic tube. Get a piece of glass tubing just sufficient in diameter to allow a pea to fit in it and move freely. Place the pea at one end of the tube, and the other end in your mouth, and suck it, when the pea will "rush" into your mouth. The cause is, that by sucking you withdraw the air from before the pea, and then the air behind it presses it forward, making it seem to rush of its own accord. All "sucking" is in like manner effected, whether it be of an orange, or the breast by an infant. The term "pneumatic" tube is only the scientific expression for "air" tube, and the cause of locomotion thus brought into action is the pressure of the atmosphere, which is found to be 141⁄2 lbs., or roundly 15lbs., to the square inch of surface. In other words, the atmosphere presses upon all surfaces at the rate of about 15lbs. to the square inch, and it is easy to conceive that a pressure of 15lbs. on every square inch of surface will constitute a considerable driving force for locomotiom.

In sucking the glass tube we simply "exhaust" it of air; the same thing occurs in the pneumatic postal tubes, only the "exhaustion" of the tubes is effected by suction pumps worked by steam.