12 



NATURE 



\Nov. 7, 1878 



conclusirely attested by the evidence of the gentleniea 

 ■whose statements I have quoted. 



I am indebted to Sir Dighton Probyn for an interesting 

 letter from Capt. Gerard, of Goona, a high authority on 

 Indian fehdae. He expresses his belief that tigers seldom 

 if ever exceed Jerdon's measurements, a tiger of 10 feet 

 I inch being the length of the largest he has ever killed 

 or seen. He refers to examples of large tigers described 

 by various observers, but he doubts tj^e accuracy of the 

 measurements, which he thinks may have been uninten- 

 tionally exaggerated. His own experience is very large, 

 his accuracy as an observer well known, and his opinion 

 consequently of much value ; but it is hardly sufficient to 

 invalidate that of others who are no less competent to 

 note and record facts, and who certainly give a greater 

 length, as the extreme growth of the tiger, than that 

 within which Capt. Gerard limits him. The matter then 

 stands thus : Mr, C. Shillingford, Col. G. Boileau, and Sir 

 C. Reid,> vouch for tigers of over 12 feet. The same 

 gentlemen, with Sir H. Green, Sir G. Yule, the Hon. R. 

 Drummond, Col. D. G. Stewart, Mr. Gumming, and Col. 

 Shakespeare vouch for tigers of 11 feet and upwards. 

 The above, with Col. J. Sleeman, Sir Joseph Fayrer, Mr. 

 B. Simson, and the Hon. Sir H. Ramsay vouch for 

 tigers of 10 feet 5 inches and upwards, all from measure- 

 ments taken before the animals were skinned. Unless 

 these gentlemen, all of whom are accustomed to shoot 

 and measure tigers, were mistaken, the question of length 

 may, I think, be regarded as decided beyond dispute. 



In conclusion, after thanking sincerely those gentlemen 

 who have given me information derived from their own 

 experience, I would just say that the mere length of a 

 tiger is not necessarily an indication of its real size. The 

 tail is included in the measurement — so tiger hunters 

 have ruled that it shall be — but the tail is a somewhat 

 variable element ; in some it is long, in others short, and 

 it is quite possible that a 9-foot 6-inch tiger with a short tail 

 may be heavier, stronger, and larger than a lo-foot tiger 

 with a long tail. No doubt anything over 10 feet is very 

 large, and those of 11 or 12 are rare and exceptional, 

 even though part of their great length may be assigned to 

 an immensely long tail. But I think that, while making all 

 allowances for errors of measurement — which doubtless 

 are not uncommon, though unintentional — there is still 

 sufficient evidence from accurate measurements to show 

 that tigers may exceed 10 feet 3 inches, and that a 

 few — perhaps rare and exceptional instances — do exceed 

 even 11 and 12 feet, J, Fayrer 



THE TELEPHONE, ITS HISTORY AND ITS 

 RECENT IMPRO VEMENTS ^ 



II, 



IN the preceding article we traced the history and 

 development of the magneto-telephone. This in- 

 strument, even if it served no other purpose, has given to 

 physicists a galvanoscope of surpassing delicacy. In the 

 columns of this journal (vol. xvii. p. 343) Prof. Forbes 

 showed how the feeblest thermo-electric currents could 

 be detected by its means, whilst the subsequent discovery 

 of the microphone was but another application of the 

 same fact. This latter instrument and the early history 

 of the carbon telephone we now propose to consider. 



In the spring of the present year Mr. W. H. Preece 

 startled every one by announcing that Prof. Hughes, the 

 well-known inventor of the type-printing telegraph, had 

 discovered that a couple of bits of charcoal, or a few 

 fragments of metal in loose contact, when in circuit with 



' Since writing the above I have been informed by General Sir C. Reid, 

 K,C.B., Bengal Army, that he has shot, and measured before the skin was 

 removed, in the Dhoon a tiger of 12 feet 3 inches. 



' " The Speaking Telephone, Talking Phonograph, and other Novelties," 

 by G. B. Prescott. Illustrated. (New York : Appletons, 1878.) — " Le 

 Til^hone, le Microphone, et le Phonographe," par Le Comte Th. du 

 Moncel. (Hachette, 1878.) Continued from vol. rviii. p. 700. 



a telephone and a voltaic cell, were able to reveal the 

 faintest tremor or even to transmit the sound of the voice 

 itself. Universal interest was excited by this discovery % 

 a direct transformation of sonorous vibrations into elec- 

 tricity was supposed to have been discovered, but soon it 

 became apparent that the explanation originally suggested 

 was untenable, and that the true theory of the microphone 

 was to be found in minute variations of current strength. 

 The quivering of the loose fragments produced variable 

 degrees of contact or of pressure, and the marvellous 

 sensitiveness of the magneto-telephone revealed these 

 otherwise inappreciable fluctuations in the resistance of 

 the circuit. 



On account of its sensitiveness, the microphone has been 

 suggested as likely to be of use in auscultation.* M. du 

 Moncel gives a form of stethoscopic microphone made by 

 M. Ducretet, and shown in Fig. 2. The microphone 

 pencil, C, rests upon a lower plate of carbon, P, which is 

 adapted to a caoutchouc capsule, T, and this again is con- 

 nected by a flexible tube to a second capsule, t', which 

 can be applied to different parts of the body of the 

 patient. Although the sensibility of the microphone can 

 to some extent be regulated by the counterpoise, P O, yet 

 still the objection to this apparatus is its over sensibility,, 

 for it reveals every noise or tremor, so that it is difficult 

 to distinguish one sound from another. It is not 

 impossible, however, that this or some other arrange- 

 ment of the microphone may ultimately be found to- 

 yield important results in the hands of a physician, 

 who has made himself skilled in its use. At the same 

 time we must bear in mind that, after its employment in 

 a surgical case by Sir H. Thompson, the large expecta- 

 tions that were formed of the microphone as an exploring 

 instrument in surgery have not as yet been fulfilled. We- 

 are not aware whether the microphone has been tried by 

 seismologists, or by military men to detect the mining; 

 operations of an enemy, though we should fear the same 

 causes that operate against it elsewhere might also occur 

 wherever it is employed. The disturbances to which the 

 instrument is subject are most conspicuous when the- 

 microphone is used, as it can be, to transmit speech. 

 Nevertheless a particular arrangement, designed by- 

 Mr. Hughes (Fig. 3), gives fair results. The two- 

 fragments of carbon are shown at c D, the upper one. 

 being attached to a light metal arm A B, controlled by ' 

 spring R, the tension of which is regulated by a screw tS 

 The whole is inclosed in a light wooden box H I G, sur- 

 rounded by a second box M j L, the end of which is 

 left open. A single carbon only, may even be used,^ 

 touching the metal arm, as is shown at E. In this case 

 the carbon is supported by a strip of paper gummed tt 

 the bottom of the box. Loud as is the articulation trans- 

 mitted by means of this arrangement, the noisy roa 

 which accompanies it, from tremors picked up by carbons, 

 render many words quite inaudible in the receiving tek 

 phone. So far, in fact, the microphone has not provec 

 a practical instrument ; it seems, however, likely to be- 

 come a useful adjunct in physical or physico-chemical 

 researches. In any case science is indebted to Prof. 

 Hughes for first making kno^ra an entirely novel, simple,, 

 and delicate instrument for the detection of minute 

 mechanical motions. 



We say first making known, for some twelve months- 

 before Prof. Hughes published his description of the 

 microphone, an arrangement designed by Mr. Edison was 

 singularly like the microphone in its extreme delicacy to 

 the minutest tremor. A couple of inches of silk ribbon 

 rubbed with plumbago and made stiff" with gum, was laid 

 upon two metal supports joined in circuit with a telephone 

 and a small battery. Such an arrangement not only de- 



^ Apropos of the microphone a literary friend sends me the following 

 extract from an ancient Turkish tract containing an exposition of the Moslem 

 creed •— " He (Allah) hears alike the loudest and gentlest sounds and sees all 

 things, even the walking in a dark night of a black ant on a^black stone, and. 

 hears the treading of its feet, and this without eyes or ears. 



