Part 6 (1/2)

The invention of Gray is a departure The sender of a e sits down at a s with it on ordinary paper and in his usual manner A pen at the other end of the circuit follows every raph letter a hundred n a check payable in Indianapolis Personal directions iven authoritatively and privately As in the case of the telephone, no intervening operator is necessary No expertness is required Even the use of the alphabet is not necessary A drawing of any description, anything that can be traced with a pen or pencil, is copied precisely by the pen at the receiving desk The possibilities of this instrument, the uses it ined that the lines draould be continuous On the contrary, when the pen is lifted by the writer at the sending desk it also lifts itself from the paper at that of the receiver

The action of the telautograph depends upon the variations in nets It has been seen that an electro-net exerts its attractive force in proportion to the current which passes through its coil To use a phrase entirely non-technical, it will ”pull” hard or easy in proportion to the strength of the passing current This fact has been observed as the cause of action in the telephone, where one diaphragm, moved by the air-vibrations caused by the voice, causes a varying current to pass over the wire, attracting the other diaphragm less or net In the telautograph the varying currents are caused not by the diaphragm influenced by the voice, but _by a pencil moved by the hand_

To sho these ine a case thatin thestream The stem of this rush has elasticity naturally; it has a tendency to stand upright; but it bends when there is a current against it It is easy enough to i down strea

Iles to it, and that the rush stands in the center of both currents It will then bend to the force of the second stream also, and the direction in which it will lean will be a compromise between the forces of the two Lessen the flow of the current in one of the streams, and the rush will bend a little less before that current and swing around to the side from which it receives less pressure Cut off either of the currents entirely, and it will bend in the direction of the other current only In a word, _if the quantity or strength of the current of both strea in any direction between the two, and its tip will describe any figure desired, aided, of course, by its own disposition to stand upright when there is no pressure_

Let us iine the rush to be a pen or pencil, and the two strea power to sway and th, as the streaine further that these two currents are varied and changed with reference to each other by the movements of a pen in a man's hand at another place It is an essential part of thethe principles involved in co a point, seenetic ith commonly in use His method he calls the ”step-by-step”

principle, and it is a striking exaenuity ement of what is reputedly the most elusive and difficult of the powers of nature The ht into practical for series of experiments In its operation it deals with infinitesimal measurements and quantities The first attempts were on the ”variable current” system, which was later discarded for the ”step-by-step” planan ordinary lead pencil may be used Froonally, their directions being at right angles to each other, and the ends of these cords enter openings made for them in the cast iron case of the instru is done

Inside the case each cord is wound on a small drum which is mounted on a vertical shaft Now if the pencil-point is ht upward or doard it is manifest that both shafts will move alike If the movement is oblique in any direction, one of the shafts will turn s of each shaft in reference to the other will be precisely governed by the direction in which the pencil-point is moved

[Illustration: DIAGRAM OF MECHANICAL TELAUTOGRAPH BOW-DRILL ARRANGEMENT]

Now, suppose each shaft to carry a small, toothed wheel, and that upon these teeth a small arm rests As the wheel turns this arine that at each slight depression between the ratchet-teeth it breaks a contact and cuts off a current, and at each slight rise renews the contact and pernet--one for each shaft--at the receiving end, and each of thesea pahich, being lifted, allows the notched wheel, upon which it bears, to turn _to the extent of one notch_ The arrangeed in many ways, and the detail of its action is unimportant in description, so that it be borne inthe shaft by drawing upon or relaxing the cords attached to the pencil-point_, an inet and ar wheel and its shaft to turn one notch, or asshaft_ Inthe pencil one inch to one side, ill suppose it permits the shaft on which the cord is wound to turn forty notches Then forty impulses of electricity have been sent over the wire, the clutch has been released forty times, and the shaft to which it is attached has turned precisely as much as the shaft has which was turned, or was allowed to turn, by the cord wound upon it and attached to the pencil

It will be reement is double There are two shafts operated by the writer's pencil--one on each side of it Two corresponding shafts occupy relative positions in respect to the auto instrument There are two circuits, and tires are at present necessary for the operation of the instru the automatic pen by connection with its two shafts which are turned by the step-by-step arrangement described, precisely asinstrument are

[Illustration: WORK OF THE TELAUTOGRAPH COLUMBIAN EXPOSITION, 1893]

To each shaft of the receiving instrument is attached an aluard to its shaft, as a bow drill is in regard to its drill These ar tablet, V-shaped, as the cords are with relation to the writer's pencil in the sending instru one of the pen-arht at the junction of the arine the pencil of the writer pushed straight upward froure the cords and pencil-pointdesk

Then both the shafts at the points of the arraraph, and of bow drill In the latter, in ordinary use, the stick and string; rotate the spool Rotating the spool will, in turn, , and this is its action in the pen-arraph] The number of impulses sent from each of these shafts, by the means explained, will be equal Each of the shafts of the receiving instrument will rotate alike, and each draw up its arh one took hold of the points of the two legs of the V, and drew theht line This ht line upward at the sa instrument pushed his pencil upward If this one movement, considered alone, is understood, all the rest follow by the same means

This is, as nearly as it may be described without the use of technical raph It must be seen that all that is necessary to describe any move pen is that the rotating upright shafts of the latter should move precisely as et their movement from the wound cords and attached pencil-points in the hand of the writer

Only one essential item of the movement remains The shafts of both instruency, capable of being autoement unnecessary to explain in detail, the pencil of the writer lifted fro on the metallic table which for of the pen fro desk

Prof Elisha Gray was born in 1835, in Ohio He was a blacksiven to chemical and mechanical experiments rather than to the industries When twenty-one, he entered Oberlin College, re all the money he spent He devoted his ti man he was an invalid Later he was not re several tiraph self-adjusting relay It was not practically successful Afterwards he was e coo Most of his earlier inventions in the line of electrical utility are not distinctively known He has never been idle, and they all possessed practical merit

For raph, he was foremost in the ranks of physicists and electricians He is not a discoverer of great principles, but is professionally skillful and accomplished, and eminently practical His every effort is exerted to avoid intricacy and clurand prize at the Paris Exposition, and was given the degree of Chevalier and the decorations of the Legion of Honor by the French Governain in 1881, at the Electrical Exposition at Paris, he was honored with the gold ree of AM at Oberlin College, and was the recipient of the degree of PhD froe For years he was connected with those institutions as non-resident Lecturer in Physics Another University gave hiree of LLD He is a member of the Aineers of England, and the Society of Telegraph Engineers of London He received an award and a certificate from the Centennial Exposition for his inventions in electricity

The saiven by the life of every noted Ae, have no place as leverages of success in any field The rule is toward the opposite The qualities and capacities that win do so without these early advantages, and all the more surely because there is an inducement to use them There is no ”luck”

CHAPTER III

THE ELECTRIC LIGHT

[Illustration]

It has been stated that nizes two classes of electricity, the _Static_ and the _Dynamic_ The difference is, however, solely noticeable in operation Of the dyna exaht Yet, with a sufficient expenditure of chemicals and electrodes, and a sufficient nu, either arc or incandescent, can be as effectively accomplished as with the current evolved by a powerful dynas, a few years ago the _thalus_, or lantern, the pride of the rural Congresshted by electricity, and an immense circular chamber beneath the dome was occupied by hundreds of cells of the ordinary form of battery The lamps were of the incandescent variety, andknow as the filament was platinum wire Vacuum bulb, filament, carbon, dynamo, were all unknown But the current, and the heat of resistance, and every fact now in use in electric lighting, were there in operation]