get out of order; does not diminish perceptibly in power when in constant use, and actually gains power when standing at rest. It will be particularly gratifying to the man of science, as it enables him to have always at hand a constant power for the investigation of its properties, without any labor of preparation. We notice among the beautiful results of this machine, that it charges an electro-magnet so as to sustain a weight of 1,000 pounds, and it ignites to a white heat large platinum wires, and may be used successfully for blasting at a distance; and should Government ever adopt any such system of defence as to need the galvanic power, it must supersede the battery in that case. Professor Page demonstrates, by mathematical reasoning, that the new contrivance of the coils affords the very maximum of quantity to be obtained by magnetic excitation.

I.

MORSE'S ELECTRO-MAGNETIC TELEGRAPH.

The electro-magnet is the basis upon which this whole invention rests in its present construction; without it, it would entirely fail. The electro-magnet is produced by coiling around a bar of soft iron, made in the form of a horseshoe, (fig. 1,) copper wire previously covered, similar to bonnet wire,

Fig.1

Fig.2

and varnished to prevent metallic contact with each other and the iron, (fig. 2.) The two terminations of the wire, thus surrounding the iron in a spiral form, are brought out at each end of the curved bar, and are connected, one with the zinc pole of a galvanic battery, the other with the platinum; the

battery being prepared in the usual manner with its corroding acid, produces galvanic electricity, which starts off from one pole of the battery, follows the wire around the soft iron, and returns to the other pole of the battery by the other wire-thus forming a complete circuit. The galvanic fluid is now passing the whole length of the wire, and, while thus passing, the curved iron becomes a strong magnet. By connecting the two ends of the bent iron with a bar of similar soft iron, it will support many pounds weight. If, while in this condition, one of the wires is removed from the battery, the cross bar falls, and with it its weights. The curved fron returns instantly to its original state. It is unmagnetized. Complete the circuit, as at first, and in an instant it is again a magnet. Break the circuit, and it ceases to be a magnet. If the battery is placed 100, or 1,000, or 10,000 feet from the magnet, yet, when the one is connected with the other by intervening wires, the effect upon the magnet is the same-making it a magnet when the circuit is complete, and vice versa when it is broken. In this way, power is produced at a point of considerable distance from the generating agent, and wholly at the command of the operator at the battery to make or destroy the power produced, with the utmost possible rapidity.

The above figure represents the most simple form of the electro-magnet, with its appropriate machinery for telegraphic purposes. A represents a side view of the bent iron bar, surrounded with its coils of copper wire, standing upon a platform D. V being an upright arm secured to D, to which the magnet, or soft iron, is permanently fastened by means of the bolt B B B passing between the prongs of the curved iron, and through the board V, and adjusting screw C. E is the projecting prong of the iron after it has passed through the coils-one only being seen. The other prong is directly behind E. G represents the end of the iron bar, or keeper, extending back so far as to cover both the projecting ends of the horseshoe-formed magnet. This iron bar, or keeper, is fastened to the lever HH, which is delicately adjusted so as to rise and fall by a pivot at I. K represents a steel spring over the lever H, and passes through a loophole L, formed from a brass wire; the lower part of the brass wire being secured to the lever H H by means of a screw at M. O is a hardened steel

point, similar to those used by manifold letter writers, and is also connected with the lever H H, and directly over the centre of the metallic roller T, in which a slight groove is made, to correspond with the point of O. R represents the standard in which the axis of the roller T freely revolves, and is a part of D. The line S represents the paper, in form of a riband, passing from its coil between the roller and the point of O. N and P are the two extremities of the wire upon the magnet A. Every part is now described; and, from what has preceded the description, bearing in mind the effect of the battery when in action upon the soft iron, by forming a complete circuit with the wires N and P, the mode of writing by the instrument may be easily comprehended by what follows. Complete the circuit, and instantly the cross bar G approaches the ends of the magnet E, until they meet in the direction of arrow W. Break the circuit, and G is carried up in the direction of arrow X, by means of the spring K. If to the roller T clockwork is attached, to give it a uniform movement upon its axis, the paper S will move with the same uniform motion under the point O; then, by completing the circuit, the point O is brought down upon the paper, which is indented to such a degree as to make it perfectly apparent, and continues to mark it in that manner so long as the circuit is closed; but, upon breaking the circuit, the marking ceases, and the point O flies from the paper, which continues passing on. If the circuit is closed and broken with the utmost rapidity, then a succession of dots and spaces upon the paper ap pears. If the circuit is successively closed and broken with less rapidity, short lines and intervening short spaces are made. If closed for a longer time and broken in succession, then the marks become longer; so that dots, short lines, long lines, and short or long spaces, are made, according to the time the circuit is closed, and the rapidity with which the paper moves under the pen. An arbitrary arrangement of these dots, short and long spaces and lines, constitute the telegraphic alphabet; by means of which, intelligence to any extent is communicated. Thus one dot may represent A, two dots B, three dots C, one dot and a line D, &c. The paper to be imprinted is fixed upon a revolving cylinder, and records despatches day and night; and this without ink, as the impressions are easily read, even by the blind. The records of the night continue entered on the morning. The alphabet is easily learned.

Extracts from a letter addressed by Professor Morse to the Secretary of the Treasury, relative to the magnetic telegraph.

That which seemed to many chimerical at the time, is now completely realized. The most skeptical are convinced; and the daily and hourly operations of the telegraph, in transmitting information of any kind, are so publicly known, and the public feeling in regard to it so universally expressed, that I need here only give a few instances of its action, further to illustrate its character.

The facts in relation to the transmission of the proceedings of the Democratic Convention at Baltimore, in May last, are well known, and are alluded to in my report to the department, June 3, 1844. (House Doc. No. 270, 28th Cong., 1st sess.) Since the adjournment of Congress in June last, and during the summer and autumn, the telegraph has been in

constant readiness for operation, and there has been time to test many points in relation to it, which needed experience to settle.

For more, now, than eight months, the conductors for the telegraph, carried on elevated posts for forty miles, have remained undisturbed from the wantonness or evil disposition of any one. Not a single instance of the kind has occurred. In several instances, indeed, the communication has been interrupted by accidents, but then only for a very brief period. One of these was by the great fire in Pratt street, Baltimore, which destroyed one of the posts, and consequently temporarily stopped the communication; but in two or three hours the damage was repaired, and the first notice of the accident, and all the particulars, were transmitted to Washington by the telegraph itself.

Another instance of interruption was occasioned by the felling of a tree, which accidentally fell across the wires, and at the same time across the railroad track-stopping the cars for a short time, and the telegraphic communication for two hours.

Excepting the time excluded by these, and two or three other similar accidental interruptions, and which, during seven months of its effective existence between the two cities, does not altogether amount to more than twenty-four hours, the telegraph has been either in operation, or prepared for operation, at any hour of the day or night, irrespective of the state of the weather.

It has transmitted intelligence of the greatest importance. During the troubles in Philadelphia the last summer, sealed despatches were sent by express from the mayor of Philadelphia to the President of the United States. On the arrival of the express at Baltimore, the purport of the despatches transpired; and while the express train was in preparation for Washington, the intelligence was sent to Washington by telegraph, accompanied by an order from the president of the railroad company to prevent the Washington burden train from leaving until the express should arrive. The order was given and complied with. The express had a clear track; and the President and the cabinet, being in council, had notice both of the fact that an express was on its way with important despatches to them, and also of the nature of those despatches; so that, when the express arrived, the answer was in readiness for the messenger.

In October, a deserter from the United States ship Pennsylvania, lying at Norfolk, who had also defrauded the purser of the ship of some $600 or $700, was supposed to have gone to Baltimore. The purser called at the telegraph office in Washington, stated his case, and wished to give notice in Baltimore, at the same time offering a reward for the apprehension of the culprit. The name, and description of the offender's person, with the offer of the reward, were sent to Baltimore, and in ten minutes the warrant was in the hands of the officers of justice for his arrest; and, in half an hour from the time that the purser preferred his request at Washington, it was announced from Baltimore by the telegraph, "The deserter is arrested; he is in jail. What shall be done with him?"

To show the variety of the operations of the telegraph, a game of drafts and several games of chess have been played between the cities of Baltimore and Washington, with the same ease as if the players were seated at the same table. To illustrate the independence of the telegraph of the weather and time of day, I would state that, during the severe storm of the