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his dermis and epidermis are thicker. I believe that these facts supply the explanation of the extreme unhealthiness of the African climate for the white man. His thin outer skin permits his system to be weakened by an undue loss of its fluids in the daytime and of its heat at night, and in this condition he falls an easy prey to some disease.

There are black men in Africa, India, and Australia, because these countries all have climates with long pronounced dry seasons. Owing to the peculiar formation of the continent of America, its tropical regions are more humid, and consequently no very dark natives are found there. Of the great Papuan race, which inhabits New Guinea and

many smaller islands in that part of the Pacific, some branches are black and some brown; but I have not been able to procure meteorological data bearing on their case.

The climate and complexions of the rainless coast of Peru correspond very closely to those of the rainless valley of Egypt, the Peruvians being perhaps a shade darker. The dry climate of the tropical part of the Andes has even affected the color of the Spanish creoles ; while in Cartagena and Guayaquil, towns with a humid climate on the seacoast of South America, their complexion is as light as that of native Spaniards, and fair hair still occurs, in Santa Fé, which is in the mountain country, only dark complexions with dark hair are found. Tschudi, indeed, asserts that the colder the climate (i. e., the greater the elevation), the darker the color in Peru.

Some of the evidence tending to show the connection of humidity and fairness in Africa is quite striking. In the mountainous region of

. Gambaragara, near the Albert Nyanza there lives, according to Stanley, a race whose fairness so struck him that he supposes that it must have come from the north. According to Lefebvre, the skin of the Abyssinians becomes lighter during the rainy season. The Bongo, Niam-Niam, and Monbuttoo tribes, whose fairness amazed Schweinfurth, inhabit a wooded and presumably a humid country, while the black Shillooks, with whom he contrasts them, dwell in a country adapted to pastoral purposes, and therefore probably dry. In the rainy regions of the Atlas Mountains there are said to be tribes among whom many individuals with blue eyes, fair skin, and red beard occur.

Similar phenomena recur in Asia. The blonde races of the Caucasus are found on its moist southern slope. The races on the dry northern declivity have a Tartar complexion. The moistest part of India is the jungle-covered southern slope of the Himalaya Mountains, and in this quarter, accordingly, we hear of white races. The Rohillas, an Aryan people, living northeast of Delhi, and the Lepchas, a Mongolian tribe, near Darjeeling, may be mentioned as examples. In the north of China proper there is a low-lying, swampy, and presumably somewhat moist peninsula called Shantung. There is some evidence tending to show that the natives of this peninsula are fairer than the rest of the Chinese. *

If this theory be correct, it is the destiny of the white race in North America to approximate in color to the aborigines. Two causes at present, to a considerable extent, counteract the effects of climate. The first is the constant influx of immigrants from the Old World ; the second, the fact that, until the great West is filled up, the struggle for existence can not become very severe, and the degree of cutaneous adaptation to climate can not assume great importance. But there are, nevertheless, indications that climatic influences are producing their natural effect. The unmixed descendants of the original settlers everywhere appear to have dark hair and a more or less sallow complexion. The writer can testify from personal observation that this is generally the case with the descendants of the united empire loyalists who settled after the Revolution in what is now the Province of Ontario. He can also testify to the darkness of the French Canadians, who derive their origin principally from Normandy, and therefore may be assumed to have at first included a large number of fair-complexioned individuals. It is remarkable that among this race a great many persons are to be seen whose features are more or less Indian in type. This, however, may (as Dr. Wilson, of University College, Toronto, supposes) be the result of an admixture of native blood.

However similar, physically, our descendants may, under the influence of climate, become to the Indians, it by no means follows that they will resemble them mentally or morally. The same struggle for existence that will eliminate the individuals ill adapted to the physical climate will also eliminate those ill adapted to the intellectual and spiritual climate, so that I am inclined to predict that the result will show, what history has indeed already established, that capacity for progress is not indissolubly connected with any particular hue.

It is obvious that on this hypothesis agreement in color does not prove, and disagreement does not disprove, community of origin. Guided by linguistic affinities, ethnologists have already in many cases disregarded color in their classifications. In the Indo-European family they include both the fair Teutons and the dark Hindoos. The white Finns and Magyars are classed with the yellow Ural-Altaic

Black Arabs and white Jews go together in the Semitic group. But the principle has not been applied throughout. The Basques and the Caucasians, between whose languages and those of the Aryan family no relationship has ever been established, are generally considered to be nearer in blood to us than those members of the Ural-Altaic group who exemplify in the fullest degree the Indo-European type of physique. Hitherto the ethnological results of investigations into the physical characteristics of different races have been mainly negative;

See a paper by J. Lamprey, in the “Transactions of the Ethnological Society" for 1867.

the principal valuable positive conclusions have been derived from linguistic researches. In the dispute as to the relative merits of the zoological and philological methods in ethnology, I accordingly side with the advocates of the latter; and, in regard to the special subject of this paper, I say with Quatrefages, in the words of Virgil, “ Ne crede colori.

TIIE CARBON BUTTON.*

By E. A. ENGLER, A. M.

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LTHOUGH the telephone seems to have sprung up among us

very suddenly, there have been steps in its development which show that the difficulties encountered in devising a means for the transmission of articulate speech have not been overcome altogether by a single stroke of individual genius, but singly by the patient and, for the most part, unrewarded labor of many. Each stage of its development was the outgrowth of suggestions obtained from previous experiments. Of the instruments which served their purpose in the discovery of the properties of the carbon button, a brief description will be given in this paper.

Sound is known to be produced by vibrations, generally of air ; differences between sounds are due to differences in vibration. There are but three essential characteristics to be noted, all dependent upon the vibrations of the air : 1. The pitch, by virtue of which a sound is called high or low, and which depends upon the number or rapidity of the vibrations; 2. The intensity or loudness, which is determined by the amplitude of the vibration ; 3. The quality by which we distinguish the corresponding tones of different instruments, and which depends on the form of the vibration. In order to obtain an exact reproduction of any sound, its pitch, intensity, and quality must be exactly reproduced ; and, to render this possible, the rapidity, amplitude, and form of the vibration must be exactly reproduced.

For producing sound at a distant place two methods suggest themselves : 1. Actually to transmit the sound vibrations through the air ; this is the method employed in the speaking tube. 2. To reproduce the sound vibrations at the distant station ; this is the method employed in the telephone. The previous development of the telegraph naturally suggested electricity as the agent to carry the vibrations from one place to another. It thus became necessary to convert şound waves into electric waves and vice versa, and experiments looking to the accomplishment of that end were begun nearly twenty years ago.

* This paper, at first intended for a special occasion, has been published at the suggestion of several friends. In its preparation, use has been made of information to be found in George B. Prescott's work on the telephone, and in the journals of science. Most of the illustrations are from Prescott's work.

The first successful experiments were made by Philip Reis, of Fredericksdorf, Germany, in 1861. He argued that if it could be found practicable to convert sound pulsations into electric pulsations, and then convert these pulsations back again into sound pulsations, the same effect would be produced as if the vibrations had been actually transmitted through the air. In his instruments a membrane rigidly secured on the sides was caused to vibrate in the center by the motion of the air produced by any sound. In the center of this membrane was a delicate circuit-breaker so arranged as to break the circuit of an electric telegraph line at every vibration, thus successively magnetizing and demagnetizing an electro-magnet at the receiving station, and causing its armature to vibrate in accordance with the vibrations of the membrane at the transmitting station. The vibrations of this armature, properly mounted on a sounding-board, set into vibration the surrounding air, which carried the sound to the ear. His first instrument is represented in Fig. 1. A is the transmitting and B the receiving instrument, supposed to be placed at different stations and connected with each other by a metallic conductor. A conical tube, a b, six inches long, four inches in diameter at the larger, and one and a half inch in diameter at the smaller end, is closed at b by a collodion membrane o, against the center of which rests one end, c, of the lever cd. This lever has electric connection with the wire of the line joining the two stations at its point of support, e. The end d of the lever rests against the flat spring 9, which can be properly adjusted by means of the screw h, and which, through the metal standard f, is connected with the battery C. At station B the conducting wire passed around the electro-magnet m, which is mounted on a sounding-box W; thence to the ground. ,Attached to the armature at the pole of the magnet is a thin plate i, which is hung on an horizontal axis projecting from the upright k; the motion of the plate can be regulated by the screw l and the spring 8. The best dimensions and most suitable adjustments of the instrument were determined by experiment. operation is as follows: When at rest the small spring n keeps the lever c d in contact at g, the circuit is closed, and the magnet m attracts the armature i. But, when by speaking into the tube a b, the air in the tube and therefore the membrane o is set into vibration, the contact at g is alternately broken and closed, and consequently the magnet at B is demagnetized and magnetized, alternately releasing and attracting the armature i. It is evident that the vibrations of i correspond in number and interval to the vibrations of the membrane o; so that the sound which enters the tube a b is reproduced at B so far as its pitch is concerned. But as the strength of the current is constant, neither the intensity nor the quality of the sound is reproduced.

In 1874 Elisha Gray, of Chicago, accomplished the reproduction of intensity and quality as well as pitch of sound by means of an instrument in which the strength of the current could be varied in exact accordance with the tone to be transmitted, and was thus enabled to

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reproduce any number of tones simultaneously without losing their specific character-a thing plainly impossible with the Reis instrument. The device used is shown in Fig. 2. T, is a mouthpiece into

T which the person transmitting sounds speaks. D, is a tense thin diaphragm connected with the line joining the two stations. To the center of the diaphragm is fastened one end of a metal rod N, whose other end dips into a jar J containing acidulated water. A metal plug

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