Menlo Park Apl 1 = 76^a

Friend Miller¹

I have a chance to sell mine yours & Batchelor’s ² Domestic Stock to the A&.P people for $5 per share ½ Cash & ½ approved notes=³ I think I can let you have more than ½ if not all cash for your 100 shares

I am to be ready to deliver them Wednesday next if the sale goes on so please put your certificate in a letter and leave it on the with^b General Lefferts,⁴ or in his care, so that I can make the delivery if the trade goes on⁵

Answer qk Yours

New York April 5— 1876^a

Rec’d from Mr T. A. Edison Certificates as per account for Thirty three hundred shares of the Capital Stock of the Domestic Telegraph Company, for which I agree to pay him Sixteen thousand, five hundred dollars one half Cash and one half notes due Six months from date without Interest— Owing to the absence of some of the parties who have decided to purchase this stock I am unable to make the settlement in full today, but now pay him Three thousand dollars in cash on account of the purchase, and am to have a few days allowance in which to make the further payments the notes and cash to be placed in Mr Edison’s hands as soon as I receive them from the several parties, and meantime all the Stock Certificates to be left in my custody— The entire settlement to be completed by April 10th 1876. ¹

N.Y. April, 8/76

My dear Edison

Eckert¹ from some source knows I am going—² Whilst I am absent he & Gould³ will renew their attempts to get you away from me—

With Hs⁴ signature which is finally necessary, although we can move without him now, we can of course secure something—⁵ now they only desire & hope to get you to yield & my ruin they think will be complete—

Your Domestic money will serve your present needs. You will hear from me in 14 days.⁶ Your pen⁷ is in good shape, so that prospectively you have ample resources, & for present your needs are meet—

My Leondon trip⁸ of course is for our mutual good, hence I simply rely on your promise to me in which I have implicit faith, that you will do nothing in Automatic or Quadruplex toPage 10 complicate until I return— You cannot finally lose because they assure you they are willing to care for you, hence you have a sure thing anyhow—

I further rely on you when I return to carry out your promise about my continued interest for the future as a means for indemnity^a for the past & our mutual interest hereafter.⁹ You told me once—Good faith needed no written contracts— Yrs tr

Menlo Park April 11 = 76

Dear Genl

Did you get the list of prices for foreign pen patents. Put your negotiations in trim as Yeaton¹ is so busy with the American Co that he will undoubtedly allow his foreign option to expire as he has only 19 days more. ² Yours

New York,Philada Apl 24 1876.^a

My Dear Edison

I’ve been thinking a good deal about the Segar¹ —and in order to get a general judgment on it—have mentioned it to a good many people— Everybody says “Capital”—not found one dissenting pvoice= and this all—accords exactly with my conclusion every time I think about it=

At all events whether or not it shall immediately become popular or not— If I had it in time to place in the Centennial² & on sale in this City—by Opening day—enough could be made out of it—simply viewing it as a novelty, to nett you &Page 12 I a good round Sum this summer Its a thing which could be nicely handled at such a show as this= I am all warmed up for it & am therefore impatient of even a moments delay in getting it in shape— I am of course just in my usual luck in having to go away on the Eve. of having something of a personal nature to give my attention to— But I will be back within 10 Days—perhaps ere this week is out— then I’m coming to Menlo—to help you through with it—If indeed you dont have it complete by that time.

I feel as if at last I was in a fair way to make something——& I never needed it more— —and am in a great hurry to get at it. I have thought of a number of points in which this will excell the Pipe—& of none in which it is inferior to it—& only very few in which the Segar could be Inferior—(all of which however^b are offset by the one element of cost—)^c

In this—the smoker has during the entire “smoke”—what in the Pipe he only has on^d the 1st lighting—that is the cool unmoistened whif which carries with it the flavor of the tobacco he smokes—making the smoking of 1st class tobacco a reality in everyway— in a pipe after a few whifs you may as well have 3 ct tobacco as 50— ³

In this—the fire is always equal in body—never gets any nearer the mouth—nor down into the nicotine—nor increases in Bulk by igniting a larger Body of Tobacco no in intensity by heating the Body of material^b which composes the material of Body^b—of the Pipe—

The mouth Piece—alone can become strong— then make it very cheap— unscrew it, & throw it away retaining the Barrel & Spring &C—

The barrel—being open at bothe ends may be swabbed out like a Rifle—& Dundrearys⁴ may even have theirs made with a Belgium twist & mirror polish inside—

Make the spring so when pushed back it will lock—so as to permit of the handy & easy filling of the barrel—then lock the barrel by the end cap—& set the spring free—

Get this up—& let me have an ample supply— Come & pay me a visit—& I’ll guarantee to show the money for one days sale on the Eve of the 10th of May—of 1000 of—“Edisons Perpetual Segar,”—

Dont lose any time in order simply to imitate the appearance of a Segar— Let that come in good time— my idea is that a nicely gotten up & elaborated arrangement will be even more popular than an imitation of a Segar— it certainly will immediately sell as a novelty—Page 13

I propose to sell Tobacco—Tobacco Pouches, &c—in connection with it—

If I was in the Country today I’d whittle one out of a Piece of Alder Bush OAs it is, I’m not at all sure I wont improvise one from a piece of Oil Driving Pipe as soon as I reach that Country Yours once more Enthuzed

New York 25. April 1876.^a

T. A Edison, Esq Menlo Park. Grand Laboratory—and general investigating Department, of Spiritual and Material Matters, Electro Motive force I × U + G ÷ A.&P. = W.U. Consolidated—^1b

You will have to come over and see me. so as to close up several matters. Am prepared to talk about your Salary² for next five years—

Close Pen matters.

Dont notify Yeatons, until I see you. Yours truly

New York April 26—1876^a

Dear Sir

Yours of inst is at hand¹ covering receipt for $500. cash, and for $2500 in notes, all in payment for Domestic Tel Co Stock.

I am obliged for your graceful compliment as to ingenuity, but really it is not deserved, as I simply carried out the agreement between us. However “alls well” &c I now enclose Note of F. W. Roebling ² to his own order and endorsed by him for $1500. due Oct 27/76. being payment for one half of Six hundred shares for which please return me receipt— I will send you more cash tomorrow or next day— As suggested in yours of 19 inst³ I called on Mr Morten to secure the information as to Fire Alarm system, and enclose a circular which he had prepared⁴ It seems to me this should have much additional matter to render it profitable for circulation? No doubt you can furnish it? Please do so that we may have a neat circular or pamphlet prepared— Will Mr Batchelor send his drawings to Mr Murray?⁵ Mr M will set to work as soon as he is posted— Time is an important element for a successful issue so please do what you can to aid us in this as in other particulars— I hope your new home is agreeable, and that the boy thrives—⁶ Our Annual election today was entirely Goulden in its character⁷ I enclose the ticket⁸ Respectfully

[Menlo Park, April, 1876?]¹

Want Merrihew² ordered to loop two good^a Washington wires into Laboratory^3b

Order on Phelps⁴ for allowing me to select from disused instruments what I require; making a list of same for your approval. Also for 100 cells Callaud battery, latter to be charged to me on acoustic account=

Also order on Division Supt whose district covers Boston & NY to allow me and assistant the use of the woires at night when the same are not used for business, that is to say the same kind of order that you gave me when I was experimenting nights on the Quadruplex ⁵

Then I shall be happy—

Spent on Acoustic to date, not paid for—

If the experiment & progress so far is satisfactory I should like for you to resume specie payments, but will not require but ½ as much as stated in Contract. ¹²

[New York?,] May 1, 1876

This Agreement made this 1st day of May 1876, between the undersigned, Thos A. Edison of Menlo Park, state of New Jersey, and^a Marshall Lefferts, of the City and State of New York.

The said Edison having invented and patented in the United States, an instrument and device known as the “Edison’s Electrical Pen and Duplicating Press” and has taken out a patent for the same in England,¹ and now agrees to patent the same in France, Belgium, Austria, Prussia, and various other countries, and hereby further promises and agrees that the said Lefferts is to have the option of purchasing from the said Edison, either or all of the Patents aforesaid, and for the countries for which patents may be taken out, such option to continue for the period of four months from and after the fourth day of May 1876, and at the following prices.Page 17

to be paid by the said Lefferts upon the assignment in due form of law, of any or all of the above mentioned Patents, and the said Edison agrees that he will not, during the said term of four months, sell, assign, or otherwise dispose of any of the said Patents, but will hold the same, subject to the sale of said Lefferts.— and the said Lefferts agrees that he will use his best endeavors to introduce the said “Edison’s Electrical Pen and Duplicating Press” to the notice of parties in Europe, and to make arrangements for their introduction, and that upon his exercising the option of purchase herein granted by the said Edison, the said Lefferts, will, upon the completion of the papers by a proper and usual deed of Assignment as prescribed for the Country for which the said Patent may be purchased, pay to the said Edison in Cash, the sum of money herein before stated for such Country which may then be required by the said Lefferts to be assigned.^b

Said payments to be made in Gold.

Thos A. Edison

New York May 2d, 1876^a

My dear Edison:—

I would like to have the 200 signal or call boxes¹ finished at the earliest moment possible, cash on delivery.²

I want to contract for 500 to 1000 more to be made at once. What will be the lowest figure for a complete improved box?Page 18

I have arranged with Mr Nelson to have Applebaugh³ take charge of the “Domestic” in addition to the Manhatten ⁴ lines, and by the end of this month hope to be able to say we are in a fair way to compete for business.

When can the 200 boxes be ready? Yours truly

[Menlo Park, May 5, 1876?]¹

My Dear Genl

I suppose you received my telegram asking you to delay negotiations on the English Patent for a fews days. ² It appears that I gave an English Gentleman named Gloynn³ an option in the first part of Febry Running 60 days after the filing of the Complete Specifctns at that time I had paid Serrell⁴ $280. Gold to send forward the papers and supposed he had done so and that their Option had expired⁵ but they⁶ came down here on saturday and said the patent was sold to T. D. Clare of Manchester the person who exhibited it before the Royal Society.⁷ I told them that was no way to do to get an option and then never say a word for months & suddenly jump on me besides I said your option expired long ago. They replied no—we have been to Serrells and he says the patent has only just been filed. =if this is true then I am fast. I have sent Batchelor over to ascertain the date of^a filing of the patent from Serrell. Should it prove that my option with them is run out what do you advise that I do; sell it to them or not,— pls send This option is only on English never had any arrangement with any one on other countries except Yeaton = Pis send G & Stock Contract⁸ by Batchelor.Page 19

I would come in today but I am working on the acoustic Telegh & I would lose entire day Yours

The laboratory records designated Volumes 8-18, covering the period 1875-79, are collections of notebook entries relating to etheric force, acoustic and multiple telegraphy, the telephone, phonograph, electromotograph, and electric light, as well as a few other subjects. Most of the drawings and notes were originally made in soft-cover tablet notebooks that Edison distributed around the laboratory. Volume 8 is thirteen such notebooks bound together. To create the other volumes, Edison’s staff removed the pages from various tablet notebooks and arranged the material topically, making tracings of the drawings.¹

The page/volume numbers were probably assigned when the volumes were assembled in 1880, after the Patent Office declared Edison’s telephone patent applications to be in interference with those of Alexander Graham Bell, Elisha Gray, and several other inventors. In letters of 16 February and 1Page 20 April 1880, Edison’s patent attorney, Lemuel Serrell, suggested that one of Edison’s assistants “sort out the drawings and evidence according to date” and “lay out all matters relating to Telephones” so that Serrell could go over the material with Edison and “number and list the drawings.”²

The drawings and notes that were taken from Volumes 9—15 for use as exhibits in the telephone interferences are not at the Edison National Historic Site.³ However, photolitho-graphed facsimiles do appear in Volume 2 of the printed court record.⁴ In assembling these materials into documents, pages excised for inclusion in the court record and pages still in the volume have been treated as equivalent—that is, as technical notes—and, because they were arbitrarily ordered when the volumes were assembled, the individual pages have been reordered if a logical progression of ideas demanded it.⁵

[Menlo Park,] May 8 1876

Keeping 1 line on two sets of instruments.¹

2 wires ac[ous]t[ic] t[ransfer]²

main line direct to Reed= X is 2 ohm spool the variation in resistance makes it hard to adjust hence failure Page 22

 

Works red Hot

Apparatus whereby 1 wire with acoustic vibraters is made to thrown another wire on two sets of insts at once all mkg 2 clomplete wires of a single one= for instance bet ny & Washn 1 wire can be the directer with acoustic Reed this reed can mdo^a make contact so as to double 10 or 15 more wires wi both through & with way station 〈Works beautifully〉

Same with a way station

Page 23Acoustic Tel ³

One reed one note higher than other. 1st part of dot sent on one reed & other part on other one reed thus giving up & down stroke distinctive causing the op[erato]r to read without trouble

Acoustic Chemical Recorder

Edison

Dated, New York, 9th May, 1876.

To the Atlantic and Pacific Telegraph Company and Jay Gould:

I am instructed on behalf of Mr. George Harrington and Mr. Thomas A. Edison and their associates, to demand of you the return of the deeds dated respectively 1st January, 9th March and 9th April, 1875,¹ purporting to be assignments from the said George Harrington to the said Jay Gould, and which were placed in the hands of said Jay Gould for a specific purpose, which has not been accomplished, and which cannot now be accomplished. ² And also to demand assignments or releases to the said George Harrington, trustee of the interests assigned by the said deeds, and the surrender of any powers of attorney therein contained. And also the delivery to the said George Harrington, trustee, of all original deeds and contracts delivered to the said Gould by the said George Harrington.³ And I am also instructed on behalf of the said George Harrington, as President of the Automatic Telegraph Company, to demand of the Atlantic and Pacific Telegraph Company, the surrender and relinquishment of possession of the telegraph lines and offices and telegraph apparatus formerly held and used by the Automatic Telegraph Company, and now held and used by the Atlantic and Pacific Telegraph Company.

And I am also directed, on behalf of the said George Harrington and T. A. Edison, to require the Atlantic and Pacific Telegraph Company to account for and pay over to the Automatic Telegraph Company the value of the use and occupation of the said lines and offices and the apparatus therein by the Atlantic and Pacific Telegraph Company, up to the time of the surrender thereof as aforesaid.

And also to require the Atlantic and Pacific Telegraph Company to desist from the use of the patented inventions of the said T. A. Edison, and to account to the said George Harrington, as trustee, for the use thereof since the said, The Atlantic and Pacific Telegraph Company, was notified in the month of August last to discontinue the use of the same.⁴

Mr. Harrington and Mr. Edison recognize and ratify the notices heretofore given to you, in August last, on behalf of the parties holding the major part of the beneficial interest in the said patents held in trust as aforesaid.⁵

Menlo Park May 16 76.

Friend Royce¹

Yours recd.² am much obliged for the information. am anxious to get the patent for the pen etc issued as it wish to raise the wind. besides its been dragging along for a great length of time.

Can you ascertain what formality it has to go through yet, if it has passed through “printing” “stationary” & “perforating Machine” Classes safely or have they dug out of the Assyrian stone tablets of Babylon an antiduluvian reference;

Regarding that despicable puppy Sawyer³ I never believed a word he ever said. Hes nothing but a bag of miasma under pressure. He’s got his two Autographic machines connected placed on a table and connected together by a rod and bevel gear under the table, to obtain synchronism. So I am told. Yours

New York May 23d 1876

Dear Sir

You will please to take notice that you must fulfil in all respects your contract with me¹ bearing date the 28th day of January 1876 as under said contract or refusal or option I did on the 29th day of January last negotiate for you the sale of the Patents for Edisons Electrical Pen and Duplicating Press in & for the Kingdom of Great Britain (according to the terms you authorised me to make) to one Jno F Gloyn who will be ready to pay for the same within the time stated in your contract with me

You will please have the transfer or assignment ready for delivery upon payment to you of the price agreed upon.

If you neglect or fail to fulfil the contract on your part youPage 27 will be held liable for all damages resulting from such failure ² Truly Yours

Menlo Park, N.J. May 29= 76

Friend Royce

The next time you drop into the Patent office please ascertain how long the Electric Pen will probably be detained in the printing stencil or stationary class if it has to pass through many classes. It makes me uneasy to see fellows running around with a wagon load of Legal tenders asking when that patent will be out=

Are the WU working the click click clicks click click clicks, from N York to Chicago regularly now.¹

Im going to send something within next six weeks to patent ofs that will make the Teleghers eyes stick out a little.² Yours;

Edison’s acoustic transfer telegraph was a novel type of synchronous multiplex system. These systems used a kind of time-sharing of the transmission line, switching rapidly between several sets of telegraph instruments. Each set was connected for only a fraction of the total time, but the switching was so fast that each set responded as if it were continuouslyPage 28 and exclusively connected to the line. A system like this could only work if the high-speed switching devices at both ends of the line remained precisely synchronized, so that each transmitter and its designated receiver were on the line at the same time.

Although numerous inventors had sought to design synchronous multiplex systems, Edison had never explored the technology in his extensive previous work on multiple telegraphy. ¹ Most attempts to realize this operating principle employed rotating disks with multiple contacts for the switching.² Edison instead tried using the electrically driven harmonic oscillators—tuning forks and metal reeds—with which he was familiar from acoustic telegraph experiments.³

New York, May 31, 1876^a

To all whom it may concern,

Be it known that I, Thomas A. Edison, of Menlo Park, in the State of New Jersey, have invented an Improvement in Acoustic Transfer Telegraphs, of which the following is a specification.²

The object of this invention is to regulate all kinds of telegraphic mechanism and causing the synchronious movement of two different machines placed at a distance from each other and connected by a telegraphic circuit.

The invention consists of two acoustic reeds, tuning forks or other bodies following the law of the pendulum ³ operated directly by electromagnetism or indirectly by the intervention of sonorous bodies or columns of air between such reeds, tuning forks or other bodies following the law of the pendulum and the electromagnets, such electromagnetic acoustical reeds are placed at the two ends of a telegraphic circuit and being provided with suitable contact breaker points, switches connections and other proper devices vibrate when properly adjusted in perfect or practically perfect unison with each other.Page 29

The invention further consists in combining with such acoustical instrument of other contact devices than is necessary to separate the reeds themselves, which contact devices serve to throw the wire upon which the electromagnets operating such reeds are placed, upon a new set of electromagnets entirely disconnected from the reed magnets, at both ends of the wire simultaneously at theat particular period of time when the wire is not transmitting an acoustical wave.

The second set of electromagnets contained in a branch circuit at both ends may be common Morse relays operating sounders and controlled by a key; the two receiving the same number of waves as the reed but not at the same time and occuring with great rapidity act upon the relay in the same manner as a constant current.

The invention further consists, in the various contact points to ensure a perfect transfer of the wire from the signalling instruments to the reed instruments and vice versa.

The invention further consists in various forms of reeds and electromagnets operating the same to suit the various conditions which arise upon long, short, and inferior telegraphic circuits.

The invention further consists, in the various methods of compensating for the mutilation of the acoustical and signalling waves by the static current and by derived currents from contiguous wires.⁴

The invention further consists, in the method of transferring the main wire from the acoustic magnets and circuit at terminals and at way stations to the signalling magnets at the same stations.

The invention further consists, in the method of transmitting from one circuit into another.

The invention further consists, in the method of translating into branch wires,

The invention further consists in the method of duplexing and quadruplexing the signalling circuit obtained by acoustical transfer.

The invention further consists in the method of transmitting two messages in the same direction upon the circuit obtained by acoustical transfer.

The invention further consists in the method of signalling (upon the circuit obtained by acoustical transfer) by the use of polarized relays and reversed currents.

The invention further consists, in the method of transferring several separate circuits from into two branches each byPage 30 means of local reeds operated by contact points upon the main line reed.

The invention further consists in transferring a single circuit on several branches simultaneously at both ends of the wire so as to allow the transmission of several distinct messages in either direction at the same time.

The invention further consists in the method for regulating machinery so as to run synchronously at both ends of the line, and the transmission of telegrams over the same wire at the same time.

The invention further consists in the method of transmitting messages upon the acoustic transfer branch as well as the other branch by a reversal of the current.

It is well known that if two bars of steel of equal length breadth and thickness be secured to a pillar that they will when acurately adjusted give out the same note when struck and make the same number of vibrations or movements in the same time. It is also well known that the reeds can be automatically kept vibrating by placing electro magnets upon one side of the bars in such a manner that they will attract the bar when an electric current passes through them, and when the current ceases the natural elasticity of the bar will cause it to spring away from the cores of the electromagnet. If a contact spring connected to a battery thence to the electromagnet thence through its wire to the bar, be properly adjusted the bar will separate from the contact spring at the moment when the bar nearly reaches the cores of the magnet, this severing of contact between the spring and the bar will open the local circuit, the magnet will lose its magnetism and the reed will recede from the cores but will again touch the spring and close the local circuit and be again attracted by the magnet and so on adinfinitum.⁵

When both reeds are allowed to break the circuit, one contracts ⁶ the other so that it is not absolutely necessary to obtain the same vibration in each that they should be acurately timed, one may even be a note higher or lower than the other the result will be that the vibrations will be the mearn of the two, but the amplitude of vibration will not be so great as it would were they in perfect accord.

These two reeds are shown in Figure 1. one at one end of a telegraphic circuit and its fellow at the other end. When arranged in this manner they run accurately together, both making the same number of vibrations in each second and independent of the battery power, which only serves to increasePage 31 or decrease the amplitude or sweep of the bars, which do not effect the proper adjustment of the various contact points which I will show in the subsequent drawings. Only a constant current circulating through the main circuit will destroy in a measure the adjustment and that is easily compensated for by simply adjusting the magnet to and from the reed.

In fig. 1. X and X′ are the two reeds, B. B′ are the bar vibrators kept in motion by the power of electromagnets m. and m′.

The main line containing batteries MB¹ and MB.² at each terminal is connected to the vibratory bars of both instruments. A and A′ being the rigid pillars or blocks that serve to secure the reeds, D. and D′ are the contact springs connected to the magnets and to batteries and earth. C. and C′ are limiting screws which serve to check the spring at that point where the reed stands when in a state of rest, and allows the main circuit to be broken at both ends at the same time, the momentum acquired carries the bar nearly up to the face of the magnets both then fly back and touching the springs D and D′ simultaneously close the circuit through therir respective magnets which again attract them.

It will be noticed that no current passes over the line at the particular period of time when the bars have left their contact springs D. and D′. hence the line is only used one half of the time.

It is these intervals or time when the line is not used for the transmission of acoustical vibrations that I transfer it over upon morse signalling instruments connected to batteries and earth at both terminals simultaneously and as the vibrations are much more rapid than it is possible to make the relay lever respond to thenm it follows that if the batteries are connected to the signalling branches at both ends a practically continuous current will pass through the relays at both ends which may be interrupted for the purpose of signalling by opening one of the branch circuits.Page 32

I am thus enabled to use the wire in the ordinary manner for sending and receiving in either direction and at the same time obtain two perfectly synchroneously moving instruments for controlling and regulating the special applications of which I shall describe in another portion of this communication.

The above described arrangement is shown in figure 2 . ⁷

X and X′ are the acoustic instruments placed at the terminals of the line. A. and A′. are the two pillars which hold the reed bars B and B′. and to which the main line is connected at both ends of the line. Upon the extreme end of each reed are two contact springs c. g. and c′. g′. on either side and facing them are contact points e. and e′. h. and h′.

To the contact points h. and h′. are connected branch wires⁸ to Morse apparatus consisting of relays, keys and a battery MB.¹ and MB.², one at each end of the wire.

The contact points e. and e′. isare connected to other branches to the battery in which is included the electromagnets M. and M′. which give the reed motion. The points e. h. and e′. h′. are so adjusted that when the reeds are in a state of rest the springs upon it do not come in contact with either points, but when the reed is vibrating it alternately comes in contact with e. e′. and h. h′. thus transferring the line at both ends simultaneously from the acoustic instrument to the Morse apparatus and vice versa with great rapidity and if the keys of both Morse instruments are closed and the reed makes two hundred movements each second there are 200 waves of electricity sent over the wire while the line is in contact only with the Morse instruments and these waves occurring so closely together and iat so rapid a rate do not allow the core of the magnet to discharge, hence a weak but practicallyPage 33 through not a really continuous current passes through both instruments attracting their levers and closing the local circuit containing the sounder (not shown) and none of these waves ever pass through the electromagnets of the reed as a different and distinct series of waves are sent to actuate the reed magnets at a time when the line is entirely disconnected from the Morse apparatus by a break on the circuit between the springs g and g′. and the contact points h. and h′. The wires 10. and 10′. form the Morse or signalling branch while the wires 5. 5′. form the second branch containing the acoustic magnets.

K and K′ are the signalling keys.

Having now shown a method of transmitting the acoustic waves to obtain a perfect syncronous movement of two machines and at the same time the transmission by Morse apparatus in the ordinary manner and practically obtaining a complete wire, I will now show the method by which I transmit two messages over this wire so obtained; by means of the duplex principle;

This method is known as the differential method and is shown in Fig. 3. ⁹

X and X′ are the acoustic regulating instruments, operated as shown in Fig. 2 . R. and R′. are the two Morse instruments placed in the branch circuits.¹⁰ These instruments are provided with double coils, through which the currents are made to pass in opposite directions, one coil is connected in the branch wire, 10. and 10′. at both stations, while the other coils are connected within an artificial circuit formed by resistancePage 34 coils S and S′. shunted with condenser when by the adjustment of the resistances S and S′. the current circulating in the artificial line is equal to the current in the main line or its effect upon the cores of the relay a perfect balance is obtained and the battery M.B.² may be included or excluded from the circuit by the signalling key or sounders K or K′ without producing any effect upon the relay at the same station, but the distant relays will respond thus allowing the transmission of two different messages over the wire obtained by the acoustical transfer.

The condensers P and P.′ serve to compensate for the static charges of the line.

It might be though,¹¹ that whereas a series of vibrations pass through one set of spools upon the differential relays that it would be impracticable to obtain a balance by passing a continuous current through the other spools in an opposite direction, but in practice no trouble arises from this cause, should it arise on working very long wires it can easily be obviated by providing the reed with another contact point which shall break the equating circuit at the same time and in the same manner.

In figure 4 . is shown the method of duplexing the transfer wire by the use of a Wheatstone breidge and it will only be necessary to describe the connections at one end of the line. ¹²

X. is one of the acoustic contracters.¹³ 10. is the branch circuit containing a part of a wheatstone bridge, n. and n.o. are two^b resistances forming two sides of the balance while the relay R. is placed in the bridge wire.

S. is the resistance forming the equating or artificial line.

K. is the transmitting key whereby the current from the battery MB′ may be made to pass through the bridge and itsPage 35 connections over the line, or not, as it is depressed or raised.

When the current from MB′ which passes through the artificial line is equal in strength to the current which passes through wire 10. to the distant station, its taking off or putting on will not produce any movement of the lever of the relay R′ but will act upon the relay at the distant station while the current from the distant station will not act upon its relay at that station will upon the relay R thus allowing two operatives to transmit therir respective messages in opposite directions.

I will here mention that the ordinary relays. R. R′ may be replaced by polarized relays and worked by single currents or by double currents, in which case the transmitting keys (or sounders which I prefer to use) are made double and connected with the main battery as shown in figure 5 .¹⁴

PR and PR′ are the two polarized relays which are shown connected in the ordinary manner for working Morse.

m and m′ being switches to throw the main circuit to earth when not transmitting.

L and L′ are the reversing transmitters which serve to send positive and negative currents over the wire by altering the direction of the flow of current from the main batteries.

It is obvious that if the polarized relays PR′ and PR are provided with extra current¹⁵ one of which is included in an equating circuit as in fig. 3 . or is placed in the bridge wire of a Wheatstone balance as in fig. 4 . the transmission of two messages at the same time is obtained.

In this case the use of the switches m. and m′ are unnecessary.Page 36

In Fig. 6. is shown connections fror transmitting one message on the transfer Morse circuit in the manner already described and another message upon the transfer circuit containing the acoustic magnets, ¹⁶ the transmission of a second telegram by the use of the acoustic circuit is obtained by taking advantage of the fact that if the reeds are made of Bell metal with an armature near their ends secured to them and facing electromagnets, the reversal of the current will not in the least effect the transmission of vibrations or decrease their amplitude, as the electromagnet not being^c polarized responds equally to both positive and negative currents.

Now the only way that an interference is possible is that in time the cores of the electromagnet which serves to give motion to the reed may be have its cores permanently magnetized.

In this case a permanently magnetized steel bar placed across its yoke can be made to balance or neutralize it all together, as the waves which give motion to the acoustic reed are always passing over the line.¹⁷

I include polarized relays PR. and PR′ in the branch circuit containing the electromagnets of the acoustic.

The operation is as follows:—

If the switch S′ is turned so as to connect the branch line direct to earth the battery n′ will send a current into the line through both electromagnets of the reeds and both polarized relays, and the tongues of both will be thrown on one side, if now the key K be closed the current will be reversed and the tongues of the polarized relays thrown to the opposite sides thus giving the signal, but the reeds will continue to vibrate,Page 37 as their electromagnets not being provided with a directionve force are indifferent to the reversal of the direction of the flow of the current; at the same time that messages are being transmitted with the polarized relays, messages can be sent with the common relays in the manner previously described.

In figure 7. is shown the connections for duplexing both of the transfer circuits (ie) both branches.¹⁸

It will only be necessary to describe the connection at one end to explain the principle.¹⁹

10. is one of the branches which only contains a Wheatstone balance in the bridge of which is a common relay. All the connections in this circuit are the same as in the wire 10. fig. 4. at X. or the connection may be as in wire 10 Fig 3. or in wire 10.^d fig 5. Two communications being sent in opposite directions at the same time.

The connection of wire 15. containing the reed magnets is similar to that shown in fig. 4 with the exception that the polarized relay PR and the electromagnet of the reed are placed in the bridge wire of the Wheatstone balance formed by the resistances 1 and 2.Page 38

3. is a resistance forming the artificial line for balanceing^b the currents from the battery MB′ so that they pass into the line but do not effect PR or the reed magnets.

The same operation takes place at the distant end; by this means I am enabled to transmit two messages by means of the instruments in wires 10. and 10′ and two messages by reversed currents polarized relays through the wire containing the reed magnets without at all interfering with the proper vibration of the two reeds, in all 5 distinct series of signals.

In figure 8. is shown the two reeds worked alone upon a single wire, ²⁰ the bars serving to transfer another and distinct wire from one set of instruments to another.²¹

22. is the controlling or directing wire containing the reeds at both terminals in circuit.

The contacts c. d. and a. b. serve to automatically open and close the main circuit and keep the reeds vibrating in unison. MB.¹ and MB.² are the two main reed batteries.

Upon the extreme ends of the bars are contact springs facing contact points e. f. and g. h. to which the two sets of instruments are connected. The other main line 20 is connected to the bars themselves so that at each vibration the line 20. is alternated at the rate of 200 times per second from N and PO. to NO and P. thus giving the operator two distinct circuits toPage 39 transmit upon, each of which may be duplexed or quadruplexed in the manner already shown.²²

In figure 9. is shown a method of connecting where one reed only breaks the circuit thus controlling the other, but it is only useful where the wire upon which they are placed is used only to transmit these waves alone and not for signalling purposes.

In figure .10. is shown the connections for a way station, X being the way station.²³ In this case the wire is transferred to A. B. and C. simultaneously and then to the other set of relays the keys in any one of the branches serving to interrupt the current and produce signalling. It does not matter how many way stations are connected in this manner to the main line, all can work as in the usual manner.Page 40

In figure 11. is shown a better form of contact for transferring on second circuits as the line is only disconnected from one set of instruments at the moment it comes in connection with the other set of instruments.

I will now show the method of synchronously vibrating a number of reeds placed in one circuit at both ends of the line; each reed serving to transfer upon two sets of instruments separate circuits. The connections are shown in fig 12 .²⁴

A and B. are transfer reeds serving to transfer if so connected the controlling line from its own magnets to branch signalling instruments connected, n. and m.²⁵

C and D are included in the same main or controlling circuit and serve to transfer the main line number 1. from thePage 41 signalling instruments 1. and 3. simultaneously and twhen to 2 and 4. creating two distinct signalling circuits.²⁶

E and F. are two more reeds which serve to transfer the main line No. 2. on 5 and 7. and 6 and 8. in the same manner as with line No. 1.

It is not essential that the reeds C. D. E. F. should be placed in the main controlling circuit as they may be reeds operated by magnets placed in local circuits which receive breaks from an extra contact point and spring in connection with the main reed. The connections for the local reeds are shown in fig. 13.

X and X′ are the primary controlling reeds, placed at the two ends of the controlling circuit and the reeds vibrate continuously in the manner already described. To the points a and b. of X and X′ may be attached the branch lines to the batteries MB ¹ and MB.² in which branches there may be inserted a key and relay with sounder attached and the same may be worked with reversed currents or the branch or transfer circuitPage 42 thus obtained may be duplexed in the manner already described. The reeds are both provided with extension upon their extreme end, opposite these extensions are springs d. and d′. whose platina tips are opposite the platina tipped contact screws c and c′. and at every vibration of the reeds the springs d and d′. are separated from the points c′ and c. thereby breaking the local circuit simultaneously at both ends of the line. In this local circuit at both terminals are several reeds, (two at each end are only shown) and local batteries LB¹ and LB². It follows that these reeds at both ends will vibrate simultaneously together and the bars of each being connected together by a line wire the wire will be transferred from one set of instruments to another and independent set of instruments as many times per second as the reeds vibrate at always at the same moment.

A and B are one set of local reeds to which the main line No 1. is connected, e. and g. are the contact points for one branch, f and h. are the contact points for the other branch; in these branches are the keys and relays 1. 2. 3. and 4 .

The arrangement of C and D are precisely the same, thus each wire is made by the acoustic transfer into two^c wires each of which is sas perfect for signalling purposes as the single wire in every respect. It is obvious that the primary vibrator may be made to close and open a local circuit in which any number of local vibrations might be included. For instance between New^b York and Washington where one company has 15 wires one of them would be set apart to work the primary reed and by the points a. and b. signalling could go on just the same as if the vibrators were not worked upon the same wire. At the same time the remaining 14 wires could each be provided with a local vibrator all placed in one local circuit which was opened and closed by the reed of the primary vibrator, and these local vibrators would split, so to speak, by transfer each of the 14. wires into two wires, each making 29 complete wires out of 15. If it was desired to work Philadelphia and Baltimore, extra primary vibrators could be inserted upon the controlling wire at those places and these made to actuate the 14. local vibrators and the wires transferred simultaneously at all points from one set of instruments to the other in a similar manner to that shown in figure 10.

I have shown two main batteries M.B.³ and MB.⁴ at X. but in practice the line No. 2. could be attached to the battery MB.³, and MB⁴— dispensed withPage 43

It is obvious that the branch or transfer circuits 1. 2. 3. 4. of A. and B. as well as those of C and D could be worked by reversed currents or duplexed either by the use of Wheatstone balance or differential relays. It is not even necessary to employ a separate local vibrator for each line as one very powerful local reed or vibrator might be used and all the contact points attached to it by being properly insulated.

The local vibrators A. B. C^b and D may be replaced with the vibrator shown in figure 14. whereby the wire is split by transfer into 4 circuits instead of two.²⁷

X is the local vibrating reed its magnet m. being included in a local circuit opened and closed by the contact points of the primary vibrator. 13 is the vibrating rod. 1 and 2. are springs with platina tips in contact with the platina points of the springs 5 and 8. The springs 1. and 2. are insulated from the reed 13. while 5 and 8. are in metallic contact with it. 6 and 7 are two limiting pins, 4 and 3. are two contact points to which are connected the branches 15 and 17. containing the polarized relays and keys 21 and 24. 20 and 25. When the reed is in a state of rest the springs 1 and 5 and 2 and 8. are in contact with each other and the tension on 1 and 2. being slightly greater than on 2²⁸ and 8. separate them from the limiting pins 6 and 7.

The points 4 and 3. do not touch, but when the reed moves to the right the spring 2. comes in contact with 3. thus throwingPage 44 the line to the branch 17 until the spring 8 touches the limiting pin 7. when connection is broken, just as this takes place the extension 9 comes in contact with the spring 12. throwing the line upon the branch 18. on its return contact is made again between 3 and 2 and 8. when the reed goes to the left and that side being provided with exactly the same devices the main circuit is thrown alternately into 15 and 16 but at no time is the main circuit thrown onto two branches at the same time; of course the polarized relays in the branches receive very short waves of current but as^b the reed makes about 300 vibrations in each second there is abundant current to give good signalling. MB¹ and MB² are two batteries one with its carbon pole towards the line while the other has its zinc pole towards the line.

23. 24. 25 and^c 26 are the double point reversing keys the lever of each being in connection with the branches or main line and the front points with the zinc pole of the battery MB¹, while the back points are connected to the carbon pole of the battery M.B.² the manipulation of the key by the operator transmits positive and negative currents into the circuit.

It is not necessary that polarized relays should be used as ordinary relays and straight currents could be used and each branch could be duplexed but I prefer to use the polarized relays as they work upon a weaker current than the unpolarized relays. I do not wish to confine^b myself to the method shown of reversing the current as a single battery could be employed and each key could reverse the same as regards its particular branch. I will also mention that switches could be inserted between the polarized relays and the keys so that the branch could be put to earth in the act of receiving. The arrangement with common relays and primary vibrator is shown in figure 15.Page 45

A and B are the primary vibrators connected and operated in the manner already described. f and e. are the two signalling relays the circuit of which is obtained by the transfer of the primary controlling circuit.

The magnets of C and D are in a local circuit opened and closed by the primary reeds.

1. 2. 3 and 4. at C are ordinary relays provided with keys the front anvils of which are all connected to a common battery, the operation is about the same as in figure 14.

In figure 16. is shown a modification of fig 15, whereby the contact points are dispensed with and an ivory surface inlaid with contact teeth is used,²⁹ it is also different as regards the number of transfer circuits, 6 being easily obtained by the use of this device.Page 46

A and B. are the primary vibrators, the reeds of which open and close the local circuit containing the local reeds C and D.

K and K′ are the reed bars; upon the extreme end are two springs g and h. tipped with a platina roller running on a flat ivory^c surface F and E inlaid with platina faced teeth to each of which is connected a wire to the several relays and keys at both ends of the line.

MB¹ and MB ² are the main batteries which work the several derived circuits.

When the reeds C and D. are vibrating the rollers g. and h. pass back and forward over the teeth simultaneously at both ends, thus connecting the line alternately in several instruments at the same time and several hundred times in each second the number of circuits obtainable being only limited to the amplitude of vibration which it is practicable to give the reeds and the delicacy of the receiving instruments to weak circuits. I have shown ordinary relays in the branch circuits for the sake of simplicity in explaining the operation but inPage 47 practice I prefer to use very high resistance and sensitive polarized relays worked by reversed currents.

In figure 17. is shown a modification of 16. whereby the ivory is in the form of a break wheel rotated with great rapidity by an electric engine regulatable by a governor or and the ivory wheel is regulatable by the reed X. ³⁰ E is a block to which is secured several contact wheels and springs in line with the inlaide metallic teeth of the break wheel g. each of which is connected to a relay key and sounder. The main line being connected to the break wheel; at each vibration of the reed X the line is alternately thrown through the relays 1. 2. 3. 4 & 5.

In practice I prefer to use a break wheel g. divided in several sections upon each of which there are several teeth one above the other and leaving off just as the next one commences, thus reducing the number of revolutions the engine must make.

This wheel would also be provided with an escape^b wheel released by the prongs of the acoustic reed X. The break wheel and escape wheel is carried around by friction. I do not confine myself to the use of an electric engine as any other regulatable source of power may be used as a clockwork.

In fig. 18. is shown a method of using tuning forks which are superior for long circuits.³¹

The connection for one terminal station is only shown.Page 48

A. is the primary vibrator which consists of a tuning fork B. The two prongs of which pass through the helices C and D;³² arranged on either side are the magnets E and F. and all are connected together in one branch running to the battery MB′, the other end being in contact with the spring 2. and obtains contact with the line by the contact of the prong of the fork with 2. the former being connected to the line. In this manner the forks at both ends are kept powerfully and continously vibrating. The spring 2 also serves to open and close the local circuit by contact with the point 3; in this local circuit is included a second tuning fork provided with 2 magnets and 1 pair of helices the same as A. which are energized by the local battery LB. This local set X vibrating in the same time as A. at the moment when the prong of B¹ leaves the spring .2. the point of B². comes in contact with the spring 5 thereby throwing or transferring the main circuit from E. C. D. F to the relay N key K to the battery MB′. The connections being similar to those already described.

X. is the local vibrator which is substantially the same as A. with the exception that the contact points upon either side of the reed shown in figure 14. are placed on the left hand side of each prong of the fork R. 1.2.3 and 4. are the branch circuits containing relay and keys.Page 49

I will now describe a method in which all the connections for the creation of signalling circuits by rapid transfer are substantially retained and at the same time each one of the circuits so obtained are again divided and retransferred, thus producing a great multiplicity of circuits. This arrangement is shown in figure 19.

I employ reeds in this case so as to make the description more easily but in practice prefer to use tuning forks similar to those shown in figure 18.

A is the primary vibrator connected in the usual manner and provided with a local point which serves to open and close the local circuit containing the local battery LB and reeds B. C. D. E and F.

The circuits 1. 2. 3. 4. obtained by transfer of the main circuit by the vibration of the reed of B, do not in this case run to the relays and keys to pass as have been previously described but are connected each to the reed of the local vibrators, which play between two contact points on either side of them, each of which is connected to a relay and key to and runs thence to abattery, thus by the vibrations of B. we obtain 4 branches or signalling circuits, and these by the vibrationsPage 50 of C and D. E and F are again subdivided into two^b each and they passing through the signalling instruments allow eight different operators to transmit as many different messages in either direction without interference with each other.

The subdivisions might be carried still further by the employment of another set of vibrators in the 8 branch circuits making 16 circuits but I do not think this would be practicable except with very powerful batteries and delicate signalling instruments.

Menlo Park June 21 1876

Dr Sir,

I have received from General Lefferts a letter with additions aby you, ¹ refusing to pay me anything fore experimenting on Autographic I admit that the Contract was for six 6 months & that it was abandoned at the expiration of that time & I agreed to do my own experimenting thereafter But the money I ask for was expended (by my books) before that Contract terminated.²

You do not say that you agree with General Lefferts Letter I therefore write you direct.³ Yours

Port Huron, Mich. June 29 1876^a

T. A. Edison Esqr

I am sorry to inform you of the condition of St RR¹ it is worse now than ever. I have done my best have submitted to every thing imposed upon me, have sacrificed my stock paid my money but at last the whole thing is a miserable failure—the consolidation is as far off as ever— Mr Stewt² stands firm against all. I am sure we are largely increasing our debt— I paid one claim to the Sheriff 129.00 cost 49.00 and today he has another and will make a levy this afternoon and I see no way of escape— if you Sir had confidence in me and WPE³ would have listened to me we could have saved Thousands of dollars— what do now is the question if I can in any way assist you & W.PE I am at your service—and only economy honesty and thoughtful business consideration can save us from loosing all we have in this Gratiot St RR—our expenses are simply ridiculous—it cost two dollars to earn one

I did hope to see a change but all the change is for the worse

I think you will have to come out here to do any thing with the road and something must be^b done to economize expense— Yours truthfully

Philadelphia, June 30, 1876^a

report on awards. ^1b

Group No.^c XXV²

Catalogue No.^c In Telegraph Department (Public Comfort) ³

Product,^c Edison’s^d American Automatic Telegraph

Name and Address of Exhibitor,^c Atlantic and Pacific Telegraph Company

The undersigned, having examined the product herein described,Page 55 respectfully recommends the same to the United States Centennial Commission for Award, for the following reasons, viz.:^c

It gives on [----]^c land telegraph lines of all lengths insulated on poles in the air, speeds of practical working which are from two-fold to ten-fold the speeds attained by the best of the other^f systems hitherto in use in America or any other part of the world. ⁴ I have myself, in the General Telegraph Office of the Centennial Exhibition, Philadelphia”⁵ witnessed the receiving of 1015 words in in 57 seconds of 1015 words from New York, and I retain for verification^h the slip on which the signals were received, and its transcription in ordinary char writing by the receiving clerk. I am informed that the speeds actually obtained for satisfactory practical practical working through different lengths of telegraph line are as follows:—

These splendid important results are obtained by the simplest and surest of apparatus, and with remarkable economy of personal skill and labour. The system is Bain’s original automatic system in all its beautiful simplicity.⁵ Where something of mechanical complication was needed for practical convenience, Mr Edison has not shrunk from it and he has given a perforating-machineⁱ (all the details of which I have examined, and admired exceedingly) with a key for each letter, and one or two more keys for stops &c, by which any one with out skill unskilled person can punch his message on the sending slip^j with perfect sureness and accuracy at a slow speed, and moderately skilled young operators at from 25 to 30 words per minute, and well skilled first class operators at 60 words per minute There is no other mechanism in the whole system except the simplest of appliances, worked by hand, for pulling the sending and receiving slips the sending slip and the receiving slip,^k through the single instruments used at the two ends whether for sending or receiving. the sending slip and the receiving slip Mr Edison’s double spring with nickel rollers seems a perfectly satisfactory solution of the problem of making the sending contacts for Bain’s system in a trustworthy manner which had been found very troublesome by manyPage 56 other inventors. In Mr Little’s resuscitation of Bain’s system,⁶ from which Mr Edison took his departure, various chemical solutions had been tried for moistening the receiving slip, and iodide of potassium had alone been found capable of marking the signals at the high speeds aimed at but it did not answer for practical was not found convenient for practical use, as the marks faded away too rapidly, sometimes before a single the^d message could be transcribed from the slip. On this important point I am favoured by Mr E. H. Johnson with the following statement by Mr E. H. Johnson⁷ [who assisted      ?]^e who assisted Mr Edison throughout all his experiments and trials for the practical development of the Bain Automatic telegraph and to whom I feel much indebted for very intelligent explanation of details all the peculiarities of the system now “which has resulted from these labours and is now reported on for award.

“All the iron-solutions recorded in the electrical books were tried repeatedly but proved to be unequal to more than 100 to 150 words per minute. It became necessary then that a solution should be discovered having a sensitiveness near that of the iodide, without its fleeting character. Mr Edison gave his attention thenceforth to chemistry and chemical experiments, and during six weeks of study and labour, day and night, made many thousands of different formulas, resulting at the end of that time in the discovery that Ferrid-cyanide of Potassium⁸ was almost as sensitive as the Iodide and that the record made upon it by an iron stilus was permanent and had other good properties.” Th

The electromagnetic shunt with soft iron core invented by Mr Edison, utilising Prof Henry’s discovery of electromagnetic induction in a single circuit to produce a momentary reversal of the line current at the instant when the battery is thrown off and so cut off the chemical marks sharply at the proper instant is the electric secret of the great speed he has achieved.

The main features main^d peculiarities of Mr Edison’s automatic telegraph shortly stated in conclusion are (1) The perforator, (2) the contact maker, (3) the electromagnetic shunt and (4) the Ferrid cyanide of iron solution. It deserves award as a great (1) The perforator, (2) The contact-maker of the sending^l, (3) the Ferrid cyanide of iron solution, and (4) (3) The electromagnetic shunt, and (4) The Ferrid-cyanide-of-ironPage 57 solution. It deserves award as a valuable addition to very important step in land-telegraphy.

conclusion of report W.T.

approval of group judges.^c

James C. Watson⁹

J. E. Hilgard¹¹

Ed. Favre Perret¹³

J. Schiedmayer¹⁵