one-third of an ohm, in place of the twenty or thirty ohms when the coil is made up of 180 feet of the much finer wire. I have had no opportunity of satisfactorily testing the limits to which the sounder is restricted, but it would probably work well enough when the resistance did not exceed ten or fifteen ohms per Daniell cell. A marked advantage is usually found to attend the sending of the currrent in that direction, which increased the power of the magnets of the telephones. And in using the sounder a little skill will elicit a considerably augmented effect. The principle of split currents may be applied to other purposes; it might offer a ready method of communicating with two adjoining stations on a railway from any intermediate point-that is to say, at any point between the two extreme telephones we could attach a battery or a telephone for sounding to, or communicating with, the attendants at the extreme telephones; or, if a battery be permanently included anywhere in the circuit, a wire alone, at any point on the line, offers the means of sounding the telephones at both stations, the wire being so used as to form an intermittent connection between the earth and the telephone line; and this might perhaps be practicable even from a train in motion, the engine and rails taking part in the earth connection. 2. An Account of some Experiments on the Telephone and Microphone. By James Blyth, M.A. DR M'KENDRICK stated, that by applying the microphone or carbon-interrupter of Hughes to the membrane of a phonograph, he had succeeded in using the latter as a transmitting instrument. With such an arrangement, speech could be heard in the distant telephone even after it had become inaudible near the phonograph. He also mentioned that a tambour of Marey, used in physiological experiments, spoke distinctly when the fine point at the end of the lever was applied to the marks on the tinfoil of the phonograph. When a tube was carried from the tambour to the ear, distinct speech could be obtained from phonographic tracings on copper foil, which were scarcely perceptible to the eye. This method also got rid of the difficulty of having the tinfoil impressions quickly rubbed out, as happened when the stillette of the phonographic membrane was employed. He also introduced to the Society a phonograph made by Messrs Macgillivray and Scobie of Glasgow, which, for loudness, was superior to any one he had yet heard. 3. Note on a Variation of the Microphone. By Following out a suggestion made by Mr Seabrook in Nature of May 30th, I mounted the three carbon blocks of Professor Hughes' microphone on, not as Mr Seabrook recommends, a plate of 3 inches diameter, but on a ferrotype plate about 6 inches by 4. This plate formed part of the top of a box, thus Plate This form I found to be extremely sensitive, as a piece of cotton woolinch in diameter falling through 1 inch made a loud sound in the telephone. When the plate was lightly brushed by a camel's hair brush the sound produced in the telephone could be heard a yard away. A small clock placed on any part of the table on which the microphone stood could be heard distinctly; also a tap on the table, or even walking on the floor, each step producing a clang in the telephone. On speaking into the open part of the box the words spoken were distinctly and loudly heard in the telephone, notwithstanding the difficulty of hearing words spoken by one's self at the same time. 4. On the Action of Heat on some Salts of Trimethyl-Sulphine. Part II. By Prof. Crum Brown and J. Adrian Blaikie, B.Sc. (Abstract.) In the former paper on this subject, the authors stated that when hyposulphite (thiosulphate) of trimethyl-sulphine is heated to about 135° C., it loses sulphide of methyl to the extent of 23.58 per cent., the salt at the same time fusing to a clear colourless liquid. On cooling, this solidifies to a hard, very hygroscopic crys talline mass. The solution of the substance does not decolourise iodine solution. These results point to (CH3)3S—O SO2 21 as the probable rational formula of the substance. Sulphite of Trimethyl-Sulphine.-This salt was obtained by the action of sulphurous acid on the hydrate. It crystallises well, but there is some difficulty in preparing a perfectly normal salt. The salt, as nearly normal as possible, does not, like the hyposulphite, give up its water of crystallisation in the cold over anhydrous phosphoric acid; at 140° C., however, it becomes anhydrous. Heated to 175° C. it gives off sulphide of methyl-8.3 grammes lost 2-32 grammes, or 27.95 per cent. On cooling, the clear liquid residue solidifies, forming a hard, very hygroscopic crystalline mass. This substance was so deliquescent that no analysis of it was made. The mode of formation leads to Note received on July 24, 1872.-In order to ascertain the nature of the crystalline substance obtained by the action of heat on the sulphite of trimethyl-sulphine, the authors converted it, by double decomposition with iodide of potassium, into the corresponding potash salt, which was purified from the iodide of trimethyl sulphine by crystallisation. This potash salt was found to agree in properties and composition with the "sulpho-metholate," or "methylsulphonate" of potash The bearing of this fact on the constitution of the sulphites is obvious. 5. On a Class of Determinants. By Mr J. D. H. Dickson, Tutor of St Peter's College, Cambridge. 6. On the Wave-Forms of Articulate Sounds. By Professor Fleeming Jenkin, F.R.S., and J. A. Ewing, B.Sc. (Abstract.) By the help of the phonograph we have continued the investigation described in a previous Communication (Proc. R.S.E., p. 582), and have now obtained about two hundred magnified traces of the phonographic records of vowel sounds spoken and sung by various voices, and of these sixty-five have been already subjected to harmonic analysis, extending as far as the sixth partial tone. In each case the results have been accepted as satisfactory only when, after the magnified trace had been obtained, the record on the tinfoil of the phonograph still gave the vowel sound satisfactorily. Our attention has hitherto been almost exclusively directed to the vowels u (the vowel sound in "food,") and o (as in "oh,") both of which are well spoken by the phonograph. The results, which are still incomplete, are briefly as follow: When a vowel sound is continuously sung without change of pitch or quality, the wave-form produced is of remarkable constancy, showing that the compound sound does not contain any, or at least any important, constituent which is inharmonic to the prime tone. A naturally high man's voice, with the comparatively small range f to f' saying u at any pitch throughout its range, produced a waveform which was substantially a simple harmonic curve of length corresponding to the pitch. The upper partials, when present at all, were present only very feebly. Thus u sung on bb gave a prime whose amplitude was 25 (in the unit of measurement used), the second partial was only 08, the third 11, and the others inappreciably small. When the same voice spoke o anywhere throughout the same range, it produced a trace which in every case consisted of a strong prime and a strong second partial (that is to say, the octave of the prime), the higher partials being feeble or absent. Experiments on this part of the scale with various voices proved that the proportion which the amplitude of the prime bore to the amplitude of the second partial might vary greatly at any one pitch, although the sounds were all sung or spoken as o, and received by the ear as (generically) that vowel. For example, on b one voice gave the ratio of prime to second as 1 to 0.87, while another voice on the same note gave the ratio 1 to 1.8. In any one voice there is not very much change in the ratio in passing from note to note. as d' or higher, the ratio of prime to than on the lower notes of this range. is a minimum for any one voice about the pitch bb, but this is a point requiring further investigation. We have not yet got any satisfactory o's above f'. When the pitch is as high second is decidedly greater It is probable that the ratio When, however, the investigation was carried lower in the scale by help of voices of a wider range, several much less simple phenomena presented themselves. Voices capable of singing bass, when singing u down the scale gave the usual simple harmonic from above a; but, at or near that note a remarkable change suddenly took place in the wave-form given by the vowel sound u. At that point it became a duplex wave, with a very small prime, which corresponded to the pitch, and an immensely strong second partial, the ratio of amplitudes being somewhere about 1 to 4. This form continued as the voice went down the scale; but in addition to the very strong second partial a weak third appeared, which became pretty strong on c. We cannot say that we have got true and articulate u's at any lower pitch. The voice of small range mentioned at the beginning of this paper continued to give the single simple harmonic form for u down to f, below which it could not go. Two other voices experimented with agreed in making the change at or near a. The excessive weakness of the prime in the lower, or what we call the duplex, form of u shows how weak a prime tone may be as compared with its upper partials, and yet fix the musical pitch. It also shows how small even the prime may be when not reinforced by oral resonance. The primes of the duplex u's, even when loudly uttered, were absolutely as well as relatively much weaker than those of the o's already described. The experiments with u seem to point to the conclusion that so long as the simple form is given the mouth cavity is adjusted so as to reinforce the prime exclusively, whatever be the pitch. When |