ELECTRIC TELEGRAPHS.

Tan old adage, "it never rains but it pours," is as fully verified in the history of scientific discoveries as by the events of life. When science rains upon us any new and long desiderated gift, it comes not in scanty drops, but torrents of inventions embody- ing the same principle in different shapes are poured down, so that we are in a perfect embarras des richesses, and know not Which of the many to choose. It has been thus with most of the great discoveries and inventions in science; for no sooner has any -given problem been solved than the successful discoverer finds

If surrounded by claimants for a share of the honour. It

has been so from the invention of printing by types down to the more astonishing invention of printing by lightning ; so it will

probably continue till the end of time ; and we doubt not that

when the two problems of squaring the circle and setting the Thames on fire shall have been solved, the "rain " will descend on

many at the same time, and multitudinous means will be at once discovered for doing what philosophers of all ages have hitherto striven for without success.

The numerous inventions of electric telegraphs are apt illustra- tions of the abundance that attends the new appliance of scientific principles to accommodate the wants of man. The various con- trivances by which electricity may be 'applied to transmit signals with the speed of lightning, have indeed made the choice of the particular means a question of no small difficulty. There are four companies now competing with one another to send messages through the earth ; and not only has each of those companies its peculiar mode of availing itself of the terrestrial currents of elec-

tricity for that purpose, but there are at least thirty other distinct plans for accomplishing the same object. In some of these ap- pliances the communications are made by the deflections of gold leaf, in others by the sounding of bells of different tones ; in some, again, by causing magnetic needles to point to letters of

the alphabet. There are also various printing telegraphs, which

will print a message delivered at one station almost instanter neously at the distant station with which the instrument is en rapport. Among the most recent of the printing telegraphs is the one invented by Dr. Howse, of the United States ; the ope- rating parts of which are arranged like the keys of a pianoforte, so that by pressing down a key marked with a letter of the alphabet a like letter is printed on paper at the other terminus of the connecting wire. Telegraphs of this construc- tion are in extensive use in America; and it is intended to enable friends in distant towns to hold direct and immediate communication with each other.

The telegraph company which has succeeded in extending the electric telegraph most widely in England, transmit their signals at present by magnetic needles; but we this week inspected an ingenious plan recently invented by Mr. Bain, and which we understand it is the company's intention to adopt, whereby the communications are actually written. The galvanic pen does nods luxuriate in flourishes ; it neither crosses its is nor dots its ids; but on it goes in one undeviating straight line ; and yet there is

such significance in its touch, that the initiated can decipher its mark more readily than he could the handwriting of most literary scribes. The line, though straight, is not unbroken ; and it is by the breaks that the letters and words are made known. To produce

this effect, a strip of paper is perforated, and then placed on a clock-work mechanism which draws it along, pressed tight against a metallic drum. The point of one of the wires which forms the

electric circuit presses on the paper as it crosses the drum ; and at each aperture it comes in contact with the metal. The paper being a non-conductor of electricity, the circuit is interrupted whilst it interposes, and is only completed at the perforated aper- tures. A similar piece of mechanism at the distant station draws a strip of moist blue paper across the drum, and a point of the con- necting wire presses also upon that. The property which electri- city possesses of discharging and altering the colours of sub- stances is applied in discharging the colour of the paper over

which the point passes on those parts where the electric circuit is not interrupted, and on the other parts a dark-coloured line is marked; consequently the breaks in the line correspond with the

perforations made in the strip of paper whereon the signals are stamped. By varying the positions and by increasing the num- ber of the perforated spaces, the letters and symbols are indicated. For example, a single small space marks one letter, a wider space another, two small spaces together a third ; and by combining the wide and narrow spaces every letter is expressed. The operation of perforating the paper requires practice to do it quickly ; but when the paper is prepared it is run through the apparatus very rapidly. Much improvement might, and no doubt will be made in this mode of making communications; for the principle seems capable of being applied even to transmitting the writing of one correspondent to another ; and merchants in London, after quit- ting 'Change, might thus send their instructions in full to their correspondents at Liverpool, which might be filed as authentic documents for reference.

We have observed that the variety of forms in which useful in- ventions of the same kind present themselves embarrass the choice. Perhaps it is this difficulty which paralyzes the Government; for, strange to say, though the wires of the electric telegraph are laid down from London to Gosport, the Government officials con- tinue to work the old semaphore on the same line, in preference to the infinitely more speedy and certain electric telegraph. Instead of being the first to encourage useful inventions, the Government

is always the last to adopt them, even when their utility has been long proved : therefore, perhaps, it was not to be expected that so great an innovation as the employment of lightning-messengers should be yet permitted. The speedy operations of the electric telegraph may well terrify the tardy-moving officials, who cannot find precedents for its use in the days of Pitt and Fox. There seems no tangibility about a thing that, in some incomprehensible manner, glides instantaneously through an iron wire and returns without any hinderance through the solid earth. Red tape can get no hold on lightning. The arms of the semaphore, on the contrary, are of wood, and may be held steady ; they work slowly, and (weather and daylight permitting) surely ;—the red tape sticks to them.