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NATURE 



{June 6, 1878 



at last this little instrument appeared, consisting, as it does, of 

 parts, everyone of which is familiar to us, and capable of being 

 put together by an amateur, the disappointment arising from its 

 humble appearance was only partially relieved on finding that it 

 was really able to talk. 



But perhaps the telephone, though simple in respect of its 

 material and construction, may involve some recondite physical 

 principle, the study of which might worthily occupy an hour's 

 time of an academic audience : 1 can only say that I have not 

 yet met anyone acquainted with the first elements of electricity 

 who has experienced the slightest difficulty in understanding the 

 physical process involved in the action of the telephone, I may 

 even go further, and say that I have never seen a printed article 

 on the subject, even in the columns of a newspaper, which 

 showed a sufficient amount of misapprehension to make it worth 

 preserving — a proof that among scientific subjects the telephone 

 possesses a very exceptional degree of lucidity. 



However, if the telephone has something to say for itself, it 

 would seem hardly necessary for me to take up your time with 

 any tedious introduction. It is unfortunate, however, that up 

 to the present time the telephone has kept all his more perfect 

 utterances to be 'whispered into the privileged ear of a single 

 listener. When he is older, he may get more accustomed to 

 public speaking, but if we force him, in his present immature 

 state, to exert his voice beyond what is good for him, it may 

 sound rather too like the pot quarrelling with the kettle, and 

 may call for the criticism with which Mr, Tennyson's Princess 

 complimented the disguised Prince on his "Song of the 

 Swallow : " — 



" Not for thee, she said, 

 O Bulbul, any rose of Gulistan 

 ShaU burst her veil : marsh divers rather, maid, 

 Shall croak thee sister, or the meadow crake 

 Grate her harsh kindred in the grass." 



Is it for this, then, that we are to forsake the luncheons and 

 lawn tennis and all the engrossing studies of the May Term, and 

 to assemble in this solemn hall, where the very air seems thick 

 with the accumulation of unsolved problems, or else redolentof 

 the graces of innumerable congregations ? 



It is not by concentrating our minds on any problem, however 

 important, but rather by encouraging them to expand, that we 

 shall best fulfil the intention of Sir Robert Rede when he founded 

 this lecture. 



It would be as useless as it would be tedious to try to explain 

 the various parts of this small instrument to persons in every 

 part of the Senate House. I shall, therefore, consider the tele- 

 phone as a material symbol of the widely sepr-rated departments 

 of human knowledge, the cultivation of which has led, by as 

 many converging paths, to the invention of this instrument by 

 Professor Graham Bell. 



For whatever may be said about the importance of aiming at 

 depth rather than width in our studies, and however strong the 

 demand of the present age may be for specialists, there will 

 always be work, not only for those who build up particular 

 sciences and write monographs on them, but for those who open 

 up such communications between the different groups of builders 

 as will facilitate a healthy interaction between them. And in a 

 university we are especially bound to recognise not only the 

 unity of science itself, but the communion of the workers in 

 science. We are too apt to suppose that we are congregated here 

 merely to be within reach of certain appliances of study, such as 

 museums and laboratories, libraries and lecturers, so that each 

 of us may study what he prefers. I suppose that when the bees 

 crowd round the flowers it is for the sake of the honey that they 

 do so, never thinking that it is the dust which they are carrying 

 from flower to flower which is to render possible a more splendid 

 array of flowers, and a busier crowd of bees, in the years to come. 

 We cannot, therefore, do better than improve the shining hour 

 in helping forward the cross-fertilization of the sciences. 



Before we go further, I wish to express my obligation to Mr. 

 Garnett for the able assistance he has given me. He has not 

 only collected the apparatus before you, but constructed some of 

 it himself. But for him, I might have given you some second- 

 hand information about telephones. He has made it possible 

 for you to hear something yourselves. I have also to thank Mr. 

 Gower, who has brought his telephone harp, and Mr. Middleton, 

 who has contributed several instruments of his own invention. 



We shall begin with the telephone in its most obvious aspect, 

 as an instrument depending on certain physical principles. 



The apparatus consists of two instruments, the transmitter and 

 the receiver, doubly connected by a circuit capable of conducting 



electricity. The speaker talks to the transmitter at one end of 

 the line, and at the other end of the line the listener puts his ear 

 to the receiver, and hears what the speaker says. 



The process in its two extreme stages is so exactly similar to 

 the old-fashioned method of speaking and hearing that no pre- 

 paratory practice is required on the part of either operator. 



We must not, however, fall into the error of confounding the 

 principle of the electric telephone with that of other contri- 

 vances for increasing the distance at which a conversation may 

 be carried on. In all these the principle is the same as in the 

 ordinary transmission of sound through the air. The different 

 portions of matter which intervene between the speaker and the 

 hearer take part, in succession, in a certain mechanical process. 

 Each receives a certain motion from the portion behind it and 

 communicates a precisely similar motion to the portion in front 

 of it, in doing which it gives put all the energy it received, and 

 is again reduced to rest. 



The medium which takes part in this process may be the open 

 air, or air confined in a long tube, or some other medium such 

 as a brick wall, as when we hear what goes on in the next house, 

 or a long wooden rod, or a metal wire, or even a stretched string. 

 In all these it is by the actual motion of the successive portions 

 of the medium that the message is transmitted. 



In the electric telephone there is also a medium extending 

 from the one instrument to the other. It is a copper wire, or 

 rather two wires forming a closed circuit. But it is not by any 

 motion of the copper that the message is transmitted. The 

 copper remains at rest, but a variable electric current flows to 

 and fro in the circuit. 



It is this which distinguishes the electric telephone from the 

 ordinary speaking tube, and from the transmission of vibrations 

 along wooden rods by which Sir Charles Wheatstone used to 

 cause musical instruments to *und in a mysterious manner 

 without any visible performer. 



On the other hand, we have to distinguish the principle of the 

 articulating telephone from that of a great number of electrical 

 contrivances which produce visible or audible signals at a dis- 

 tance. Most of these depend on the alternate transmission and 

 interruption of an electric current. In some part of the circuit 

 a piece of apparatus is introduced corresponding to this instru- 

 ment which is called a key. Whenever two pieces of metal, 

 called the contact pieces, touch each other, the current flows from 

 the one to the other, and so round the circuit. Whenever the 

 contact pieces are separated the current is interrupted, and the 

 effects of this alternation of current and no current may be made 

 to produce signals at any other part of the circuit. 



In the Morse system of signalling, currents of longer and of 

 shorter duration are called dashes and dots respectively, and by 

 combinations of these the symbols of letters are formed. The 

 rate at which these little currents succeed one another depends 

 on the rate at which the operator can work the key, and may be 

 increased by mechanical methods till the receiving clerk can no 

 longer distinguish the symbols. 



But the capability of the telegraph wire for transmitting 

 signals is by no means exhausted ; as the rapidity of the succes- 

 sion is increased, the ear ceases to distinguish them as separate 

 signals, but begins to recognise the impression it receives as that 

 of a musical tone, the pitch of which depends on the number of 

 currents in a second. 



Tuning forks driven by electricity were used by Helmholtz in 

 his researches on the vowel sounds, and the periodically inter- 

 mittent current which they furnish is recognised as a most 

 valuable agent in physical and physiological research. The tuning 

 forks are of the most massive construction, and the succession of 

 currents goes on with the most inflexible regularity, so that when- 

 ever we have occasion to follow the march of a process which 

 takes place in a short time, such as the vibration of a violin 

 string or the twitch of a living muscle, the tuning fork becomes 

 our appropriate timepiece. 



Apparatus of this kind, however, the merit of which is its re- 

 gularity, is quite incapable of adapting itself to the transmission 

 of variable tones such as those of a melody. 



The first successful attempt to transmit variable tones by 

 electricity was made by Philip Reis, a teacher in a school at 

 Friedrichsdorf, nearHomburg. On October 21, 1861, Reis showed 

 his instrument, which he called a telephone, to the Physical 

 Society of Frankfort on the Main, He succeeded in trans- 

 mitting melodies which were distinctly heard throughout the 

 room. 



The transmitter of Reis's telephone is essentially a make and 



