Automatic, Duplex, And Quadruplex Telegraphy - 3

Automatic, Duplex, And Quadruplex Telegraphy - 3

Flattered by their success, Messrs. Harrington and Reiff, who owned with Edison the

foreign patents for the new automatic system, entered into an arrangement with the

British postal telegraph authorities for a trial of the system in England, involving its

probable adoption if successful. Edison was sent to England to make the demonstration,

in 1873, reporting there to Col. George E. Gouraud, who had been an associate in the

United States Treasury with Mr. Harrington, and was now connected with the new

enterprise. With one small satchel of clothes, three large boxes of instruments, and a

bright fellow- telegrapher named Jack Wright, he took voyage on the Jumping Java, as

she was humorously known, of the Cunard line. The voyage was rough and the little Java

justified her reputation by jumping all over the ocean. "At the table," says Edison, "there

were never more than ten or twelve people. I wondered at the time how it could pay to

run an ocean steamer with so few people; but when we got into calm water and could see

the green fields, I was astounded to see the number of people who appeared. There were

certainly two or three hundred. I learned afterward that they were mostly going to the

Vienna Exposition. Only two days could I get on deck, and on one of these a gentleman

had a bad scalp wound from being thrown against the iron wall of a small smoking-room

erected over a freight hatch."

Arrived in London, Edison set up his apparatus at the Telegraph Street headquarters, and

sent his companion to Liverpool with the instruments for that end. The condition of the

test was that he was to send from Liverpool and receive in London, and to record at the

rate of one thousand words per minute, five hundred words to be sent every half hour for

six hours. Edison was given a wire and batteries to operate with, but a preliminary test

soon showed that he was going to fail. Both wire and batteries were poor, and one of the

men detailed by the authorities to watch the test remarked quietly, in a friendly way:

"You are not going to have much show. They are going to give you an old Bridgewater

Canal wire that is so poor we don't work it, and a lot of `sand batteries' at Liverpool."[4]

The situation was rather depressing to the young American thus encountering, for the first

time, the stolid conservatism and opposition to change that characterizes so much of

official life and methods in Europe. "I thanked him," says Edison, "and hoped to

reciprocate somehow. I knew I was in a hole. I had been staying at a little hotel in Covent

Garden called the Hummums! and got nothing but roast beef and flounders, and my

imagination was getting into a coma. What I needed was pastry. That night I found a

French pastry shop in High Holborn Street and filled up. My imagination got all right.

Early in the morning I saw Gouraud, stated my case, and asked if he would stand for the

purchase of a powerful battery to send to Liverpool. He said `Yes.' I went immediately to

Apps on the Strand and asked if he had a powerful battery. He said he hadn't; that all that

he had was Tyndall's Royal Institution battery, which he supposed would not serve. I saw

it--one hundred cells--and getting the price--one hundred guineas-- hurried to Gouraud.

He said `Go ahead.' I telegraphed to the man in Liverpool. He came on, got the battery to

Liverpool, set up and ready, just two hours before the test commenced. One of the

principal things that made the system a success was that the line was put to earth at the

sending end through a magnet, and the extra current from this, passed to the line, served

to sharpen the recording waves. This new battery was strong enough to pass a powerful

current through the magnet without materially diminishing the strength of the line

current."

[4] The sand battery is now obsolete. In this type, the cell containing the elements was

filled with sand, which was kept moist with an electrolyte.

The test under these more favorable circumstances was a success. "The record was as

perfect as copper plate, and not a single remark was made in the `time lost' column."

Edison was now asked if he thought he could get a greater speed through submarine

cables with this system than with the regular methods, and replied that he would like a

chance to try it. For this purpose, twenty-two hundred miles of Brazilian cable then stored

under water in tanks at the Greenwich works of the Telegraph Construction &

Maintenance Company, near London, was placed at his disposal from 8 P.M. until 6

A.M. "This just suited me, as I preferred night-work. I got my apparatus down and set up,

and then to get a preliminary idea of what the distortion of the signal would be, I sent a

single dot, which should have been recorded upon my automatic paper by a mark about

one-thirty-second of an inch long. Instead of that it was twenty-seven feet long! If I ever

had any conceit, it vanished from my boots up. I worked on this cable more than two

weeks, and the best I could do was two words per minute, which was only one-seventh of

what the guaranteed speed of the cable should be when laid. What I did not know at the

time was that a coiled cable, owing to induction, was infinitely worse than when laid out

straight, and that my speed was as good as, if not better than, with the regular system; but

no one told me this." While he was engaged on these tests Colonel Gouraud came down

one night to visit him at the lonely works, spent a vigil with him, and toward morning

wanted coffee. There was only one little inn near by, frequented by longshoremen and

employees from the soap-works and cement-factories --a rough lot--and there at daybreak

they went as soon as the other customers had left for work. "The place had a bar and six

bare tables, and was simply infested with roaches. The only things that I ever could get

were coffee made from burnt bread, with brown molasses-cake. I ordered these for

Gouraud. The taste of the coffee, the insects, etc., were too much. He fainted. I gave him

a big dose of gin, and this revived him. He went back to the works and waited until six

when the day men came, and telegraphed for a carriage. He lost all interest in the

experiments after that, and I was ordered back to America." Edison states, however, that

the automatic was finally adopted in England and used for many years; indeed, is still in

use there. But they took whatever was needed from his system, and he "has never had a

cent from them."

Arduous work was at once resumed at home on duplex and quadruplex telegraphy, just as

though there had been no intermission or discouragement over dots twenty-seven feet

long. A clue to his activity is furnished in the fact that in 1872 he had applied for thirtyeight

patents in the class of teleg- raphy, and twenty-five in 1873; several of these being

for duplex methods, on which he had experimented. The earlier apparatus had been built

several years prior to this, as shown by a curious little item of news that appeared in the

Telegrapher of January 30, 1869: "T. A. Edison has resigned his situation in the Western

Union office, Boston, and will devote his time to bringing out his inventions." Oh, the

supreme, splendid confidence of youth! Six months later, as we have seen, he had already

made his mark, and the same journal, in October, 1869, could say: "Mr. Edison is a

young man of the highest order of mechanical talent, combined with good scientific

electrical knowledge and experience. He has already invented and patented a number of

valuable and useful inventions, among which may be mentioned the best instrument for

double transmission yet brought out." Not bad for a novice of twenty-two. It is natural,

therefore, after his intervening work on indicators, stock tickers, automatic telegraphs,

and typewriters, to find him harking back to duplex telegraphy, if, indeed, he can be said

to have dropped it in the interval. It has always been one of the characteristic features of

Edison's method of inventing that work in several lines has gone forward at the same

time. No one line of investigation has ever been enough to occupy his thoughts fully; or

to express it otherwise, he has found rest in turning from one field of work to another,

having absolutely no recreations or hobbies, and not needing them. It may also be said

that, once entering it, Mr. Edison has never abandoned any field of work. He may change

the line of attack; he may drop the subject for a time; but sooner or later the note-books or

the Patent Office will bear testimony to the reminiscent outcropping of latent thought on

the matter. His attention has shifted chronologically, and by process of evolution, from

one problem to another, and some results are found to be final; but the interest of the man

in the thing never dies out. No one sees more vividly than he the fact that in the interplay

of the arts one industry shapes and helps another, and that no invention lives to itself

alone.

The path to the quadruplex lay through work on the duplex, which, suggested first by

Moses G. Farmer in 1852, had been elaborated by many ingenious inventors, notably in

this country by Stearns, before Edison once again applied his mind to it. The different

methods of such multiple transmission--namely, the simultaneous dispatch of the two

communications in opposite directions over the same wire, or the dispatch of both at once

in the same direction--gave plenty of play to ingenuity. Prescott's Elements of the Electric

Telegraph, a standard work in its day, described "a method of simultaneous transmission

invented by T. A. Edison, of New Jersey, in 1873," and says of it: "Its peculiarity consists

in the fact that the signals are transmitted in one direction by reversing the polarity of a

constant current, and in the opposite direction by increasing or decreasing the strength of

the same current." Herein lay the germ of the Edison quadruplex. It is also noted that "In

1874 Edison invented a method of simultaneous transmission by induced currents, which

has given very satisfactory results in experimental trials." Interest in the duplex as a field

of invention dwindled, however, as the quadruplex loomed up, for while the one doubled

the capacity of a circuit, the latter created three "phantom wires," and thus quadruplexed

the working capacity of any line to which it was applied. As will have been gathered

from the above, the principle embodied in the quadruplex is that of working over the line

with two currents from each end that differ from each other in strength or nature, so that

they will affect only instruments adapted to respond to just such currents and no others;

and by so arranging the receiving apparatus as not to be affected by the currents

transmitted from its own end of the line. Thus by combining instruments that respond

only to variation in the strength of current from the distant station, with instruments that

respond only to the change in the direction of current from the distant station, and by

grouping a pair of these at each end of the line, the quadruplex is the result. Four sending

and four receiving operators are kept busy at each end, or eight in all. Aside from other

material advantages, it is estimated that at least from $15,000,000 to $20,000,000 has

been saved by the Edison quadruplex merely in the cost of line construction in America.

The quadruplex has not as a rule the same working efficiency that four separate wires

have. This is due to the fact that when one of the receiving operators is compelled to

"break" the sending operator for any reason, the "break" causes the interruption of the

work of eight operators, instead of two, as would be the case on a single wire. The

working efficiency of the quadruplex, therefore, with the apparatus in good working

condition, depends entirely upon the skill of the operators employed to operate it. But this

does not reflect upon or diminish the ingenuity required for its invention. Speaking of the

problem involved, Edison said some years later to Mr. Upton, his mathematical assistant,

that "he always considered he was only working from one room to another. Thus he was

not confused by the amount of wire and the thought of distance."