In connection with the register there is. a ribbon of paper passing from the role between two small metal rollers of the re gister. This strip is drawn through be tween the rollers by their motion, they revolving towards the paper roll, drawing in the paper. Motion is given to these rollers by a train of clockwork gear wheels, which are moved by the weight below the machine. The upper small roll has a small groove running around its periphery, and the ribbon of paper is drawn through against its under surface. The instrument to indent the paper is a pen-lever. It is suspended on a pivot axis at its middle, and its action is like a but the stroke it makes is very short—not over the one-eighth of an inch at both ends. This pen-lever is very nicely poised, and at its extreme end from the paper its stroke is nicely regulated by a set or button screw. There is a metal pen attached to the lever and fixed on a pivot like a walking-beam. When one end is drawn down, the other end flies up, and having a steel point on it it marks a strip of paper running along a roller, which is drawn along between other two rollers. Now, by letting the other end of this pen cone up, the steel point drops, and then it is thrown up again, leaving a space between the two marks on the paper. Now, as the paper is always moving, and as the point is held to it for a longer or shorter time marks are made of dots, spaces and dashes—thus . for E, and — for L, and — . for F, and thus by a combination of dots, spaces and dashes, the whole al phabet is formed, and these letters made into words, and the words into sentences —compose the message. An electro magnet is used on Morse's telegraph to operate the walking-beam pen. It is fit ted with an armature, whose attraction and withdrawal gives motion to the lever or walking-beam; the breaking and clos ing the circuit is effected by a key of brass insulated by ivory at Philadelphia, and writes the messages in New-York.
The magnet in connection with the re gister, is made of a piece of soft iron, pure and free from carbon, sulphur, Std., and is wrapped round with fine copper wire, covered with silk. This coil of wire is called a helix. It is attached to the wire of the battery by a metallic connection at one end, and the other end of the helix —for it must be made of continuous wire —is attached to the wire from the other end of the battery, thus forming part of the electric circuit. This magnet is made almost always of a U form, but this is not so essential. This electromagnet has no attractive force except when the electric circuit is closed and the fluid rushing along the wire, and then its attraction is considerable. The end of the pen lever has the steel pen on it, so that when the operator at Philadelphia presses his hand upon the key, the circuit is closed, the end of the pen-lever above the magnet is drawn down to the magnet, and the pointer at the other end is thrown against the strip of paper. Whenever the finger is lifted off the key, the circuit is open, the magnet loses all attractive power, and the pointer then drops and does not tench the paper. It will thus be observed that,
by tapping on the key at Philadelphia the circuit is broken and closed to New York, and the electromagnet actuates the pen-lever to produce the characters we have described, which are put to gether to make words, and the words then put together to make sentences. There is a key and register placed on the same table at every station ; and this is necessary for the reception and trans mission of messages. Each station has a battery and each register has a register ing magnet, which produces the marking and is in the local circuit. But there is another magnet called the receiving mag net placed in the circuit of the main ; it also forms a part of the apparatus of the register. The office of the receiving magnet is to close and break the circuit of the register magnet. It is on the exclusive use of this instrument and the combina tion, that the value of the Morse patent is based. At the distance of 80 miles the electro flu id becomes so attenuated in pow er that it would not be capable of indenting the paper. To render the attenuated cur rent available, the receiving magnet is in terposed, differing from common electro magnets in the length and fineness of the helix, 8000 feet of wire, well covered, be ing no uncommon length ; the lever at tached to the armature of this magnet is so delicate as to affect the surface if coat ed with a little dust, or even strongly breathed on. The immediate use of it is to break and close the circuit, consisting of the register magnet, small battery, and sufficient connecting wire.
Grove's battery, though objectionable on account of the nitric acid vapors, is still the most economical. The zinc cyl inders of the battery are 2 lb. weight each, and cast very smooth. • Sulphate of soda is added to the sulphuric acid in the zinc cell ; this prevents local action and renders reamalgamation unnecessary. The number of the cells give efficiency to the battery. Eighteen members of Smee's battery, each of an inch square, are com petent to work through 80 miles ; a single cell, no larger than a thimble, will work through six miles. A series of 80 of Grove 'a battery is the average number for 150 miles. The "main battery" does not require to be charged oftener than once in 5 weeks. The acids of the "local battery" require daily replenishment. The use of poles for the support of wires is universal in this country. In Prussia, the wires are buried under ground and covered with gntta percha. In England they are generally encased in a tube and lie upon the ground or but little buried: latterly they are being placed on poles similar to the practice of France and this country. The height of the poles set in these states vary, being on an average 30 feet, buried 5 feet in earth, and the diameter at the top being not less than 6 inches ; on these are placed glass caps or rests for the wire, which is of iron, weigh ing from 800 to 830 lbs. per mile. It is either single or twisted, naked or galvan ized. The naked wire is generally pre ferred, and costa from 6 to 10 cents a lb.