I was thinking to myself recently "what was invented first, the microphone or the telephone" - and investigating that, I ran into something very interesting, a device called the "pulsion telephone" which was invented by Mr. Lemuel Mellett, of Boston, U.S.A. about 1888 or 1889.
There is very little information on the internet about it. Here are some references that I found :
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"A Telephone in 1665?" by Richard Grigonis
http://technews.tmcnet.com/bus...
[EXCERPT]
" However, later in the 19th century, "mechanical phone" systems — essentially elaborate versions of "two cans and a string" were actually used in areas not served by Bell's phone system (and which evaded any of Bell's patents). Some were complete exchanges with operator switchboards, such as Lemuel Mellett's "Pulsion Telephone" invented in 1888 for use on American railways.
A newspaper article from 1889 reads as follows: "The Pulsion Telephone was a mechanical telephone which really seems as if it might rival the ordinary telephone, at any rate for moderate distances, has been recently exhibited on a 3 miles line, between Finchley-road and Hendon, on the Midland Railway [Editor's Note: near London], under the name of the 'Pulsion Telephone.' It is the invention of Mr. Lemuel Mellett, of Boston, U.S. [Editor's Note: Actually he was from Newton and then Somerville, Massachusetts.] The principle seems to be to have on the resounding-plate a number of small coiled springs held at one end only; these respond to various harmonic vibrations, and the vibration of the wire is taken up and reinforced, giving great distinctness of utterance. It seems not to matter much whether the wire is twisted or passes through loose earth. One peculiarity is that it can be tapped at any point by resting a hat upon the wire, a useful quality in case of accident, though evidently unfitting it for private messages."
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Tin can telephone
https://en.wikipedia.org/wiki/...
" History [EXCERPT] - For a short period of time acoustic telephones were marketed commercially as a niche competitor to the electrical telephone, as they preceded the latter's invention and didn't fall within the scope of its patent protection. When Alexander Graham Bell's telephone patent expired and dozens of new phone companies flooded the marketplace, acoustic telephone manufacturers could not compete commercially and quickly went out of business. Their maximum range was very limited, but hundreds of technical innovations (resulting in about 300 patents) increased their range to approximately a half mile (800 m) or more under ideal conditions. An example of one such company was Lemuel Mellett's 'Pulsion Telephone Supply Company' of Massachusetts, which designed its version in 1888 and deployed it on railroad right-of-ways, purportedly with a range of 3 miles (4.8 km)."
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The Pulsion Telephone
https://archive.org/details/js...
SCIENCE December 27, 1889
[ Transcribed by NSR, proofread by Alex. Modern spellings for words in the text are enclosed in brackets.]
THE PULSION TELEPHONE.
A curious scene was enacted recently at a place called Child's Hill, on the Midland Railway, near London, England. What took place there, as vouched for by Engineering, was as follows. A party of gentlemen alighted from the train and ascended the embankment. Here one of them reached up to a wire stretched along the telegraph poles, and, placing the crown of his hat flat against it, he commenced a conversation with some unseen correspondent. The answers to his questions and remarks came back quite audibly to the group gathered around him, while those who felt sceptical [skeptical] as to the reality of what was being enacted before them, removed to a distance, and, pressing the wire against their ears and cheekbones, heard the return messages for themselves. After some desultory conversation, the unknown speaker was asked to give a good shout, and in reply he jodelled [yodeled] with such vigor that a boy plodding his way along the cutting, at the opposite side of both up and down lines, looked with amazement. He was at least eighty or one hundred feet distant, and yet he evidently heard the yell transmitted along the wire and received into the crown of an ordinary silk hat. It was quite impossible that he should have caught the original sound, for it was uttered in a cabin built on the side of the line at the Welsh Harp station, more than a mile away, and probably was not directly audible for one hundred yards. Those who were on the embankment knew that it was transmitted by means of a new mechanical telephone, for they had already listened to the same voice at Finchley-road station, which is 3½ miles from the Welsh Harp.
When every one had satisfied himself that spoken words, whistling, and musical sounds could be received without special apparatus, the party re-entered the train, and went on to the Welsh Harp station, where they found several lines erected in the grounds of the local hotel. One of the lines starts from a small cabin in the grounds ; it then proceeds to a post on the margin of the lake, and goes right across to a hut on the opposite bank. The distance is between a fourth and a third of a mile ; and as this wire is not particularly tight, and only starts at a height of about ten feet above the water, it will be readily understood that it must lie for nearly its entire length in the mud which forms the bed of the lake. Another line traverses the gardens ; its supports are formed by branches of trees, around several of which it is wound three times, and is then led off at an angle to its original direction. In another instance a row of statues are made to carry a line, which is laid upon any part of them which furnishes a convenient guide. This line is so slack that it can be bent into S form by the thumb and forefinger. The various circumstances appeared, however, to make but little difference to the instruments, and in all cases conversation could be carried on with the greatest ease, and often could be heard a foot or two away from the receiver.
The instrument by which these curiously constructed lines were made to give such remarkable results is the property of the British Pulsion Telephone Company. It is the invention of Mr. Lemuel Mellett of Newton, Mass., and already several hundred instruments are at work in Boston and elsewhere. The construction is so exceedingly simple, that one is filled with wonder that it can effect so much. The receiver, which also acts as a transmitter, consists of a wooden case, divided into two parts by a metallic diaphragm held by a clip-ring and screws. In the centre of the diaphragm is a hole through which there passes the line wire, having at its end a button to take the pull. So far there is no special novelty to distinguish the telephone from the old pill-box and string. The new feature consists in a set of resonators placed over the diaphragm to re-enforce its vibrations. These resonators may be made in many different forms ; those used on this occasion are spiral rings of various lengths, and made from wire of different gauges. One set of springs is festooned between the screws which hold the diaphragm, while others are held at one end only, and project upwards and inwards within the case. These resonators are chosen experimentally of such dimensions that each will be set into vibration by some one or more of the tones which are usually found in the human voice. Consequently the faintest vocal tremor imparted to the disk is immediately taken up by them, and immensely magnified. This is done both at the transmitting and receiving ends, the result being that the wire is put into intense molecular vibration of a hitherto unappreciated character. It is evidently not merely lateral vibration, like that of a guitar string, for such motion would certainly be damped in the wire laid in the lake ; it would also greatly suffer in the case of a span strung so slackly that at the centre it rests for many feet on the ground, yet such a span was shown to work reasonably well. It is evident, however, that the vibration is not purely longitudinal, for if it were it should be transmitted through a coil of wire flung loosely on the ground ; and this, we understand, is not the case. It would, however, be a waste of time to try and formulate a theory apart from experimental investigation. What principally concerns us now is the fact that a mechanical telephone has been constructed, which will speak with absolute distinctness for three and a half miles, and which is simple, cheap, and, most important of all, free from induction. It is easily conceivable that its performances may be much improved ; new forms of resonators may be found that have a nearer affinity to the tones of the voice than those already tried. Two vocal chords form the source of all the sounds we can utter, even if we be as gifted as Patti, and it seems possible that some material may be found more nearly allied to their action than wire helices. Although these can vibrate in harmony with the tones of human language, they have not the same quality of sound, and the metallic resonance which they impart to the articulation they transmit is not altogether an improvement.
[END]
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The Library of Congress > Chronicling America
https://chroniclingamerica.loc...
The Arizona sentinel. August 30, 1890
Waterbury evening Democrat. January 28, 1890
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> google books
https://books.google.com/
> Lemuel Mellett - Pulsion Telephone
English Mechanic and World of Science: With which are ..., Volume 50
https://books.google.com/books...
ENGLISH MECHANIC AND WORLD OF SCIENCE: No. 1,295. Jan. 17, 1890. p. 414
THE NEW MECHANICAL TELEPHONE.
[ Transcribed by NSR, proofread by Alex. Modern spellings for words in the text are enclosed in brackets. The illustrations appear in the text just as they appear in the original publication. References in the text to illustrations is on page 415. ]
The phenomena of sound are so familiar that one little suspects them to be amongst the most difficult to explain. There is still much confusion of thought in writing about acoustics,
Fig. 1
Fig.1 (enhanced)
and the conflict of theories has been well exemplified in the history of this science. In this age of textbooks it seems odd to find it commonly stated that there is no really excellent and comprehensive work dealing with this subject yet published. But although our knowledge of sound requires to be systematically collated and arranged, it remains a fact that our scientists have accumulated a vast store of observations on the physical properties of sound. Amongst the earliest observations on the phenomena of sound that can justify claim to be scientific were those which proved that a sound can travel in other media than air, and faster in certain media than in others. The old experimentalists having noticed this fact, set themselves to discover the velocity of sound in air, and it is interesting to notice that a recent determination by Mr. Star at the Cape of Good Hope differs but little from the earliest calculated results of which there is any record. We now know that the velocity increases with the temperature and is proportional to the square root of the absolute temperature reckoned by the air thermometer ; so that if a denote the coefficient of the expansion of air, and t the temperature in Centigrade degrees, the velocity of sound in feet per second at any temperature is given by the formula
v = 1090 √1 + a t
As Star's experiments were based upon comparison of observations made by the sense of hearing alone, his results contain fewer elements of error than those obtained by the ordinary methods.
Sound is propagated along the ground ; and in ancient books it is frequently observed that the marching of soldiers and the trampling of horses can be detected at a distance by applying the ear
Fig.2
Fig. 2 (enhanced)
to the ground. It has evidently long been known that sound can travel through solids.
Perhaps the earliest to measure the rate of propagation of sound in solids were Messrs. Biot and Martin : they experimented at Paris upon the water-pipe system over a length of 951
Fig. 3
meters. When one end of this system was struck with a hammer, an observer at the other end heard two sounds, differing by an interval of 2.5 seconds. Now, since the time through air, calculated under the conditions of the experiment, was 2.8 seconds, it was obvious that the
Fig. 4
first sound heard was transmitted by the metal. The rate for iron estimated from these data is 10400.7 ft. - that is, about nine times as great as the rate through air ; but it must be remembered that the caulking of the pipes considerably delayed the transmission.
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ENGLISH MECHANIC AND WORLD OF SCIENCE: No. 1,295. Jan. 17, 1890. p. 415
Fig. 5
The velocity of sound in solids is now found by producing vibrations in thin rods and determining the pitch of these vibrations. The length of the rod is ℷ / ₂ [ gimel symbol over 2] where ℷ [gimel symbol] is the wavelength and the number n [oblique n] of the vibrations per second is obtained from the pitch. With these data the velocity in centimeters per second is given by the equation :
v = n ℷ .
One of the most recent determinations of the velocity of sound in steel (sp. density = 7.85) gives 18412.2 ft. per second.
Wertheim, by indirect methods, has determined that if the velocity of sound in air be taken as unity, that of copper is 11.167 ; steel, 14.361 to 15.108 ; iron, 15.108 ; brass, 10.224.
It is easy to surmise the influence of such observations upon men of intelligent and original mind. Biot and Martin's results must have suggested the possibility of transmitting the voice through iron. The first, however, to distinctly formulate the idea was Philip Reis, of Friedrichsdorf, who defined telephony as the art of reproducing sounds at a distance from their source.
But although the advantages of being able to transmit sounds through media other than air early suggested themselves, and although the principles were easy to grasp, it was reserved for the mechanical ingenuity of more modern times to develop and apply them.
Perhaps the earliest approach to the mechanical telephone as we understand it was made by Wheatstone in 1831 ; his "magic lyre" experiment demonstrated that by connecting the sounding-boards of two musical instruments by means of a thin rod of wood, a tune played upon one will be faithfully reproduced by the other. The sounding-boards of Wheatstone's musical instruments suggested the more convenient sounding-box, and it was soon found that a stretched cord would do equally well to transmit a sound from one box to another ; thus before ever the ordinary electric telephone was heard of physicists were aware that sound could be transmitted over a considerable distance by a simple mechanical device. Soon after this we find several patents granted for the protection of various forms of this instrument ; but these were all crude and clumsy, little adapted for practical use.
The discovery of the electric telephone and its rapid development seem to have put the mechanical telephone entirely in the shade for many years : it degenerated into a mere toy known as the "lover's telegraph," which was a slender apparatus consisting of two parchment membranes stretched on rings connected at the centre be a silk thread. However, during the past 15 years numerous attempts have been made to improve the old-fashioned toy with a view to useful service.
A large number of patents referring to mechanical telephones have been taken out within the last few years in different countries ; some inventors have substituted discs of thin metal for the stretched membrane, and others have used wire instead of silken strings. A few of these have met with a fair share of success, notably one in which the sounding-box was replaced by a disc built up of thin strips of willow wood. When the connecting line of such an instrument is made taut, and sounds such as those of ordinary speech are produced in front of one of the discs, certain "pulses," as it were, are transmitted along the line and communicated to the second disc, which, in turn, communicates them to the air, thus reproducing the sound. Such telephones are moderately well suited for purposes of domestic telephony and to office work : but even in these cases their scope is very limited.
The latest modification of the mechanical telephone is, like many other modern improvements, of American origin. The invention is due to the ingenuity of an electrician - namely, Mr. Lemuel Mellett, of Newton, county Middlesex, Massachusetts - who has named it the Pulsion telephone. Before proceeding to the description of this instrument, it may at once be stated that it is absolutely independent of any magnetic or electric current, and therefore requires neither battery power nor insulation. In general plan the Pulsion telephone resembles the older form of mechanical telephones, and Mellett's improvement relates chiefly to the efficiency of the diaphragm or disc.
The apparatus is contained in a circular sounding box about 5 in. diameter and 3 in. deep. The disc is preferably of metal, and is in connection with a series of small metallic spiral springs located in a case some 3 in. or 4 in. in diameter situated behind the disc.
Fig. 1 gives a rear view of one form of the Pulsion instrument. The cap (vide infra) is removed in order to show the interior of the case and arrangement of the spiral springs. The arrangement is peculiar, but is said to be the most effective, having been determined by experiment so as to produce harmonised [harmonized] vibrations. These spiral springs are called "vibrators" or "resonators." The vibrators need not necessarily be springs ; they may consist of musical reeds or strings or other metallic device capable of vibration : they appear to exercise the function of magnifying or accumulating upon the connecting line-wire the vibrations which sounds set up when their waves impinge upon the diaphragm or disc.
Fig. 2 is a transverse section of the apparatus taken along the line marked x⎯x in Fig. 1. This drawing exhibits the form of chamber that is usually preferred ; other forms may be used, but they are said not to be so efficient, on account of complication due to resonance. The case a [oblique a] of the instrument is composed of wood fitted with a cap, a¹ [oblique a superscript one] , which connects it to the mouthpiece ; the case and cap together form the chamber a³ [oblique a superscript three] . The beginning of the transmitting wire is shown at a⁴ [oblique a superscript four], and a³ [oblique a superscript three] is an orifice through which this wire passes out. The cap a¹ [oblique a superscript one] , as in ordinary electric telephones, is provided with an opening, b [oblique b] , to which the mouthpiece is attached, and this opening is fitted with the disc or diaphragm b¹ [oblique b superscript one] . In this drawing the beginning of a flexible tube, attached to the opening b [oblique b] , is indicated : such an arrangement is often very useful. The disc b¹ [oblique b superscript one] is connected to the transmitting wire a⁴ [oblique a superscript four] by a metallic button, b² [oblique b superscript two] , having its loop or eye inserted through an opening in the disc, and to which the wire is attached. The chamber a² [oblique a superscript two] contains the vibrators c [oblique c] . These are clamped to a ring c⁴ [oblique c superscript four] by means of screws c¹ [oblique c superscript one] and washers c³ [oblique c superscript three] , well shown in Fig. 1. [NOTE > very difficult to see because of the cursive (hand drawn) letters and numbers] The screws are inserted through washers, ring and disc into the cap a* [oblique a * illegible superscript]. In some forms of the instrument the resonators are secured by screws fastened into the case a [oblique a] . The vibrators are evidently arranged to intensify the effect of the vibrating disc upon the transmitting line-wire. They are of various sizes, and will vibrate to different tones.
As these vibrators are really the great feature of the pulsion telephone, it may be desirable to examine the other forms which Mr. Mellett uses. Sometimes they may consist, as shown in Fig. 3, of thin strips of metal or spring tongues, so chosen and arranged that on vibrating in turn they give out the successive notes of the scale : such an arrangement as this will vibrate with any tones which harmonise [harmonize] with those notes, and will respond to the vibrations of the disc when in metallic communication with it.
The vibrators may also be strings or wires of various lengths, stretched taught across the chamber a² [oblique a superscript two] , just as the strings of a piano are arranged under tension across the sounding-board. These strings vibrate in harmony when the disc with which it is in metallic connection is set in vibration by speech or other sounds. This form is shown in Fig. 4, and Fig. 5 is a transverse section of the same instrument ; the explanatory letters are the same as those in Figs. 1 and 2 ; but f f [oblique double f] indicate the commencement of flexible listening tubes. The case is sometimes modified, thus, the cap may constitute nearly the entire case or shell, and be closed in by a plate through which the line wire issues.
A fourth form of vibrator is also used which gives excellent results, and is simpler than either of the three perviously described ; it may consist of a single spring coiled like a wire clock-gong, as in Fig. 6. The chamber, with its springs,
Fig. 6
disc, cap, and mouthpiece, may be used both as a transmitter and receiver, the two discs being joined by the line-wire.
With regard to the transmitting line, a copper wire suffices, or, better still, a double steel wire, the two parts being slightly intertwisted [intertwined]. In connection with this we may remember the superior velocity of sound in steel as compared with that in copper, quoted in the early part of this paper. It is, of course, quite unnecessary to insulate the wire, and it is entirely free from induction.
The connecting or line-wire must be taut in the immediate vicinity of the transmitter and receiver ; but it is not requisite to the successful transmission of sound that the whole wire should be strained tight ; the greater part may be quite slack, and even frequently grounded ; preferably grounded in order to reduce resonance if the line be short. The proper tension is applied to the line-wire by means of short guy-lines d [oblique d] , fastened to posts d¹ [oblique d superscript one] , as shown in Fig. 7.
The pulsion telephone was submitted to severe tests a few weeks ago on the Midland Railway, when the line-wire was looped up to the ordinary telegraph-posts from Finchley-road to Hendon, a distance of more than three miles, reckoning by the track of the wire. Conversation through this length of line was exceedingly easy ; in fact the tone reproduced was purer than when the distance was a few hundred yards. Tested first over a taut wire, verbal messages, singing, and the playing of a musical-box were perfectly audible, but equally good results were obtained through a slack wire.
Another experiment over a length of wire of about one-third of a mile, laid along the bottom of the Welsh Harp water, was quite as satisfactory. Notwithstanding the immersion of the wire, and the mud which must necessarily have surrounded it, conversation was carried on without the least difficulty ; in fact there was an absence of that resonance which was noticeable
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ENGLISH MECHANIC AND WORLD OF SCIENCE: No. 1,295. Jan. 17, 1890. p. 416
Fig. 7
with short, taut wires, and the sounds were purer and more mellow. One of the most remarkable properties possessed by the pulsion telephone, and which places it a long way ahead of other mechanical telephones, is that the line-wire may come in contact with buildings, be bent round corners, and even be coiled tightly round the limbs of trees.
The line may be tapped, and a number of branch lines, d* [oblique d *illegible superscript] Fig. 8, connected with it so that the same message may be transmitted simultaneously to several points. The line may even be tapped by merely placing a hat or stick upon the wire ; herein exists a mixed advantage.
Fig. 8 also shows the line wound round the limb of a tree. In this case the coils are preferably separated by a slight distance from each other to reinforce the line and increase its efficiency of transmission when the wire is turned at a right angle. The efficiency, however, is not perceptibly impaired when the line leaves the tree at any other angle. In the gardens at the Welsh Harp practical test of this property was made ; the wire was twice tightly twisted, at an interval of some yards, round small branches of trees, and the effect of the transmitted voice was not in the least spoilt.
The pulsion telephone can be fitted with flexible tubes, mouth and ear-pieces, which are very convenient ; such an arrangement was described in a paper on the graphophone, which appeared in these columns last September. In Fig. 5 such listening-tubes are indicated at f f [oblique double f] .
The power of this simple system of telephony to convey sounds to a distance clearly is most surprising ; the apparatus not only transmits, but
Fig. 8
attunes vocal and instrumental sounds imparted to it with but little reduction or modification.
We believe that when the apparatus is spoken into, sound-waves impinge upon the disc, and the complex motion of the air is transferred to the wire, by the wire to the second disc, by that disc to the air, and by the air to the ear of the distant listener. But there are many things which happen en route which are not so obvious, and which appear to be very difficult to understand. How, for instance, do the alternate compression and rarefaction which we associate with our conception of the progress of a sound comport themselves along a wire which may be taut, slack, grounded, looped, bent round corners, coiled round trees, and immersed in water along different portions of its length? We believe that no explanation of the entire modus operandi of the pulsion instrument has yet been advanced, and its behaviour [behavior] has been to none more surprising than to the scientific men who have recently experimented with it.
From its extreme simplicity, Mellett's telephone is manifestly a cheap instrument. It is claimed that the system can be installed at from 30s. to 40s. per mile.
Although the appearance of this pulsion instrument in this country dates but a few weeks ago, the system has been in successful operation in the United States for more than twelve months. A company is, however, being promoted called the British Pulsion Telephone Company (Limited), with Sir Edward Reed, M. P., chairman, which will work the patent on this side of the Atlantic.
The pulsion telephone has already commended itself experimentally to the notice of several railway companies and to the post-office. We think there is good reason for it to attract the attention of the War Office, the police, and the great mercantile, manufacturing, and business organisations [organizations] throughout the country.
Without going so far as to say that a great future awaits Mr. Mellett's invention, it may safely be asserted that the monopoly of the electric telephone will be considerably threatened, and that the pulsion telephone will form a most useful aid in facilitating communication over distances not too great. ⎯ J. T. N.
[END]
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COMMENTARY by NickyNick 18 November 2019
After reading through all of the above material and looking carefully at the diagrams in the article THE NEW MECHANICAL TELEPHONE in the ENGLISH MECHANIC AND WORLD OF SCIENCE: No. 1,295. Jan. 17, 1890 - I believe there is enough information at this point for a person to make a pulsion telephone and test it to determine if it actually operates as described.
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NOTE > this is a work in progress and I invite comments
or information from anyone to post on this thread
NSR
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