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them carries at its upper end a table which can be caused to rotate by clock-work if required; the other carries a pencil which moves over the table. If two pens be used two and a half inches apart, two curves will be traced, not exactly similar, but which combine in the stereoscope to give a solid figure. By changing the relative motions of the pendulums, very curious forms of curves have been obtained, resembling those given by biaxial crystals under the polariscope.

Mayer has written an illustrated article in Nature on the phonograph of Edison, calling it, in Indian parlance, "the sound-writer who talks." After a detailed description of the instrument and the mode of operating it, he describes his method of getting the form of the indentation in the foil. A delicate lever has a point on the under side of the shorter arm, which, by turning the cylinder, is made to traverse the indented groove. At the same time a style of copper-foil, attached to the longer end of the lever, moves over the smoked surface of a piece of glass held vertical, and reproduces the curve magnified in the ratio of the arms. A cut is given of the indentations, of the tracing thus made from them, and of the corresponding manometric flame-curve of König, showing their identity. Impressions have been got by Edison on copper-foil and on Norway iron.

At the April session of the National Academy in Washington, Dr. Edison gave an exhibition of the phonograph, after which various speculations were indulged in as to the possible uses of the instrument in the future. There are two advantages which the anthropologists may gain from it. If a savage were to utter his thoughts in front of the phonograph in his vernacular, and the foil were carefully submitted to some learned society, the language could be exactly reproduced. The endless confusion which has arisen by the adoption of various alphabets in securing vocabularies would thus be avoided. Again, the most cultivated languages change their pronunciation, and all peoples in passing through various stages of culture change their methods of vocalization. Let a series of phonographic sheets be struck off, stereotyped, and preserved with a proper register, and centuries hence the philologist will have the material for a comparative study.

Ellis has described some results obtained by Jenkin with

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an apparatus by which he obtains vertical sections of the impressions made on the tin-foil of the phonograph, magnified 400 diameters, and called "speech-curves." In the word tah, for example, intoned, there is first the "preparation,” the curve gradually but irregularly rising; then the “ tack" '—a bold serrated precipice, with numerous rather sudden valleys; next the "glide"--a perfect tumult of curvatures, which gradually settle down into the "vowel " proper. This remains constant for a considerable number of periods, and vanishes away gradually to silence. This curve Jenkin has submitted to analysis, reducing it to its separate pendular curves, and has succeeded in tracing out as many as five partial tones. The results differ materially for different speakers, and Jenkin is endeavoring to classify these speechcurves into genera. Thompson proposes to improve the sibilants in the phonograph by placing a strip of card or watchspring across the opening edgeways, so that the voice impinges on the edge of the strip. The aspirates are also well spoken by such an instrument.

Jenkin and Ewing have studied elaborately the form of the sound tracings produced by Edison's phonograph. With reference to the vowels, these observers note that if a set of vowel sounds be spoken to the phonograph, and then it be made to speak at several different velocities of rotation, no difference can be detected in the quality of the sounds. This they regard as contradictory of Helmholtz's statement that each vowel sound has a characteristic note of definite pitch. Moreover, they have observed that the wave form of the markings produced by any vowel sound does not remain unchanged at all pitches; but whether these changes are due to alterations in the amplitudes of the constituents or to variations of phase is not determined. Subsequently, in a paper before the Royal Society of Edinburgh, they announced the curious fact that both vowels and consonants are unaltered by being spoken backward. Words such as ada, aba, aja, ete, could be readily identified whichever way the cylinder was turned, even by persons ignorant of what had been said. Moreover, they find that ab said backward becomes ba, thus proving that a reversible part really constitutes an element of speech. Thus putting the word noshäeesossa on the cylinder, and turning it backward, it repeats association

beautifully. Preece has described two phonographs made in England from Edison's descriptions. In one of these the rotation was rendered uniform by means of clock-work, thus maintaining the identity of the sounds; in the other the receiving membrane was of paper, and seemed to be the loudest.

Blake has devised and practically applied a very ingenious method of recording articulate vibrations by means of photography, and has obtained some very interesting results. The apparatus consists of a mirror of steel capable of oscillating about a diametral axis, to the back of which is attached a lever, by which it is attached to the centre of a telephone disk, arranged with the usual mouth - piece contrived by Peirce. Whenever the disk is caused to vibrate, the mirror oscillates with it, and a beam of sunlight thrown on the mirror from a heliostat describes lines of light on a suitably placed screen. If this screen be movable at right angles to these lines of light, and carry a sensitive collodion film, the light oscillation is recorded upon the prepared surface as a more or less complex curve having the peculiarities of the sound-wave which caused it. Representations of the curves of various sounds accompany the paper.

Pfaundler has given, in a communication to the Vienna Academy, the results of some physiological experiments to determine the question whether two isolated sound-pulses. can produce a sensation of tone, either alone or by repetition. His first experiments were undecisive, but upon repeating them with the aid of Baumgarten's reflection-tones, he was able to answer the above question in the affirmative. Subsequently, using a siren with two air openings, analogous to Baumgarten's method, he confirmed his results.

HEAT.

Victor Regnault, whose death took place on the 19th of January, 1878, was a man of the highest scientific eminence. Born at Aix-la-Chapelle in 1810, he entered the store of a draper in Paris, and at twenty the École Polytechnique, where he remained two years. He then went to Lyons, occupying the chair of chemistry, and worked at research so successfully that in 1840 he was elected to the French Acad

emy, and appointed professor in the École Polytechnique. In 1841 he was made Professor of Physics in the Collége de France. His removal to Paris changed the character of his investigations. First he made his celebrated research on specific heat, in the course of which he invented the air-thermometer in its present form; then he studied the phenomena of expansion, vapor tension, and hygrometry. In 1854 he was made Director of the Sèvres Porcelain Manufactory, and improved considerably the ceramic art at that place. The death of his son Henri, an artist of promise, on the battlefield during the Prussian war, depressed him exceedingly; and on his return to Sèvres after peace had been declared, the discovery that the results of his last great research on the heat phenomena accompanying gaseous expansion, drawn from over 600 observations, had been destroyed, seemed to shatter still more his nearly exhausted frame. He never recovered from these shocks, but died on the day that the artists of Paris were laying their wreaths upon the grave of

his son.

1. Thermometry and Change of State.

Negretta and Zambra have contrived a new deep-sea thermometer, described and figured in Nature. To a cylindrical bulb containing mercury a tube is fitted, which is contorted and constricted near the bulb, and is enlarged at the remote end, from which end it is graduated. When the bulb is held downward, the mercury expands as usual, but when it is reversed, the column breaks at the narrowed portion of the tube, flows to the other end of this, and is there read. Hence, if the thermometer be lowered with the bulb downward, and reversed on attaining the desired depth, the reading on coming to the surface will represent the temperature at the time of reversal. To prevent the errors caused by pressure, it is enclosed in a glass sheath.

Himly has proposed to observe melting-points electrically by coating the bulb of a thermometer with silver to make it a conductor, which is then thickened with copper deposited electrolytically. The bulb is coated with the substance whose fusing-point is to be determined, and, when cold, is placed in mercury, which is in the circuit of a battery and electric bell. When the mercury is heated to the temperature at which the substance melts, the metallic contact is

completed, and the bell rings. The temperature observed on the coated thermometer at this instant is the meltingpoint desired.

Pictet has sought to determine experimentally the cause of the difference between transparent and opaque ice, and finds that it is due to the temperature at which the ice is formed. When frozen at temperatures between 0° and — 1.5° C. it is as clear as crystal, but when frozen below -3° it is whitish and of less density, its cohesion being also diminished. The causes of this whitish opacity are two in number-first, the presence of air bubbles in the ice, and, second, the irregularity of the ice crystals, which destroys its optical homogeneousness. If a current of air be passed through the water while freezing, the ice is clear and transparent, no matter how low the temperature at which it is frozen.

Gernez has studied the phenomenon of supersaturation in salt solutions, and finds that other liquids besides watersuch as carbon disulphide, the hydrocarbons, phenols, and especially the alcohols-show this property. A salt which does not give supersaturated solutions with one solvent never yields them with another; nor is the result attained by adding a substance such as dextrin to increase the viscosity. Sodium carbonate, calcium nitrate, magnesium sulphate, lead acetate, and alum yield supersaturated solutions most easily. In the case of all five, however, crystallization ensues only on the introduction of crystals of an isomorphous substance, and the latter lose this property if heated above a certain temperature, 98°, for example, for alum. Gernez gives a list of 120 substances which possess the property of yielding supersaturated solutions.

Mallet has examined the liquid contained in a cavity in a specimen of green fluorite from Alston Moor, in Cumberland, Eng., the cavity being irregular, 6 mm. long, 2.5 wide, and 1 deep, and filled with liquid in which was a readily mobile bubble. From the experiments which he made upon this liquid at different temperatures he concludes that it is simply water.

Handl and Pribram have described, in the Proceedings of the Vienna Academy, a new method for determining boilingpoints, depending on the well-known law that the temperature

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