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General Gallifet has found evidences of glacial action in the Desert of Sahara. M. C. Tissot has discovered in Morocco the ruins of Banasa, a city founded by Augustus, and described by Ptolemy, but whose site was latterly unknown. M. Duveyrier has discovered a race of Berbers south of Algeria called Imobagh. They are white, and with them the custom of sex is reversed. The men alone wear vails, and consider it dishonor to expose their faces. The women alone are acquainted with the art of writing, and they exercise great influence in politics. Professor Blyden has penetrated Faluba, a country lying to the interior of the west coast, and to the northeast of Sierra Leone. It was found to be a land of extensive and fertile plains, with great agricultural capacity. The people are orderly, well fed, well clothed, and very desirous of intercourse. Gold is said to be abundant in certain parts. Mr. Bayard Taylor, writing from Cairo, Egypt, this year, describes that country as making wonderful strides toward civilization, principally through the exertions and influence of the Khedive. The country is traversed with railways, the plantations supplied with steam-engines, the cities undergoing change in conformity to European style, and the religious intolerance of the people, with their prejudice to strangers, dying out. Two of the most remarkable facts observed by him are the rapid spread of the English language, and an extraordinary change in the climate. The winters have grown so cold that fires, for which the houses are unprovided, are desirable. Rains, too, once unknown, have become common. At Cairo, he saw two of a race of dwarfs that dwell in the heart of Africa. The largest was about four feet tall. The statement of Herodotus regarding the existence of a race of pigmies in Africa is, therefore, the expression of a fact.

News has been received lately from Dr. Nachtigal, the German explorer, who has succeeded in reaching Waday in safety. Waday lies to the eastward of Dar-Fur, about 15° N. latitude. Owing to the peculiar ferocity of the people, no other European has succeeded in accomplishing the feat just achieved by Dr. Nachtigal. Within the past twenty years Doctor Vogel and Moritz von Beurmann both perished in the attempt. The country is poor, and the people exceedingly barbarous, brutal, and immoral. They cannot even build perpendicular walls of mud and straw. Every afternoon they get drunk on a native

strong beer called melissa, during which time it was until recently more than the life of even an Arab was worth to venture into the streets. Adultery, theft, and disturbance of the public peace are punished with immediate death. Gerard Rohlfs has accomplished a journey of seventeen hundred miles over the Libyan Desert. His objective point was the conjectured Oasis of Kufrah, which he failed to reach, being stopped by a shifting sea of sand, in which neither man nor camel could walk. He visited the Oases of Farafrah and Dakhel. The former is poor and thinly peopled, but the latter is extremely fertile, and has a population of seventeen thousand, while it could easily support ten times that number. The desert surrounding these oases is composed of alternate plains of sand and walls of ragged rock, rising sometimes to the height of fifteen hundred feet. The temperature in this desert is extraordinarily low, the range being from 23° to 36° Fah. at six A. M.

Dr. Livingston, the great African explorer, has at length finished his useful career. His last journey was from Unyanyembe to Lake Bangweola, begun in August, 1872. His object was to visit four fountains said to exist to the east of this lake, and to give rise to the Lulua and the Lufira, which form the Great Lualaba, and to two other streams flowing south to the Zambesi. He also proposed visiting the copper mines of Kantanga, and the underground habitations in the Kabogo mountains. These objects he is believed to have accomplished. On his return to Unyanyembe he was compelled to wade for days through water waist-deep. This exposure brought on dysentery, from which he died, at Lobisa, on the 5th of May, 1873, after fifteen days' illness. His body was carried to England and placed in Westminster Abbey. His maps and journals have all been recovered.

The British Expedition to Ashantee, under Sir Garnet Wolseley, for the suppression of the slave-trade, has been completely successful. Coomassie, the capital, was taken, and Coffee, the king, captured and made to pay a tribute to the British Government. The country is described as covered with forests, and crossed by three ranges of mountains. It is characterized by a remarkable absence of birds and animals. Gold exists, generally in paying quantities.

SCIENTIFIC DISCOVERIES DURING

1873 AND 1874.

The past eighteen months have been replete with scientific discovery. In almost every branch of science there have been new avenues opened to research or new accessions of fact. In astronomy, Mr. Abbott, of Tasmania, has observed important changes in the great southern constellation of Argo. The dark spaces in the nebula are becoming more extended, more defined, and are filling up with small stars. This is a remarkable instance, among the few known, of rapid changes in the configuration of nebulæ. The discovery of a companion to Procyon was made in March, 1873, by Struve. This is of much interest, as the new planet is supposed to be the cause of the minute variation in the movement of Procyon. Five small planets, and probably a sixth, have been found between Jupiter and Mars. A new planet of the eleventh magnitude was discovered by Perrotin on the 16th of June, 1874. Its location is 162 h. right ascension, 22° 32' declination south. Two of the smaller moons of Uranus have been re-discovered through the great. telescope recently erected at Washington. These were first observed about twenty-one years ago by Tassell, but were subsequently lost. Seven new comets have also been discovered, one of which, during the latter part of June and in July, was visible to the naked eye in most parts of the United States, and attracted a great deal of attention. Investigations into the phenomena of nutation and precession indicate periodical changes in latitude of points upon the earth's surface, by which the polar regions are gradually shifted in the course of many thousand years. The existence of an atmosphere around the moon, explaining certain anomalies in the occultations of some stars, has been indicated by the investigations of Neison. An error of one-twelfth of a mile has been discovered in the difference in longitude between Greenwich and Paris, and corrected by Mr. J. E. Hilgard. Important results are expected to follow the observations of the coming transit of Venus, and great preparations have been made for the purpose by all the principal governments of the world. The United States alone has equipped eight stations. The transit occurs on the 8th of December, during the night, and therefore will be visible only in the Southern Hemisphere.

The investigations of Lockyer and Meldrum into meteorological phenomena indicate a connection between the fluctuations of sun spots and the periodical variations in resemblance and severity of cyclones in the Indian seas. Attempts to establish a similar connection with regard to rainfall have been made in India and Europe, but the result is only partially successful, the chances of the existence or non-existence of such a connection being about equally divided. A connection between the spots and variations in temperature of the atmosphere has, however, been positively established by Köppen. The International Meteorological Congress, held at Vienna in 1873, agreed upon a system of uniform and simultaneous observations for all parts of the world. This system has been already adopted by all of the leading nations of Christendom, and even by Turkey and China, and the result will doubtless be speedy and important advances in meteorological knowledge.

The application of electricity to illumination is said to have been successfully accomplished by Mr. Ladiguin of St. Petersburg. A piece of carbon or other bad conductor is placed within a glass tube filled with gas that will not combine with carbon at a high temperature, and then hermetically sealed. The carbon, being gradually and equably heated, is said to emit a soft, steady, and continuous light. The cost is said to be considerably less than that of ordinary coal gas.

A discovery of much importance to physicists and practical photographers is the recent invention of chemical compounds that may at will be rendered sensible to rays of the least or greatest refrangibility. More striking and not less important in its way is the discovery by Prof. Mayer, of the Stevens Institute, of a new method of analyzing the most complicated sounds that occur in nature. A membrane is placed near the sounding body. Attached to a point of the membrane are several fibres of raw silk, each of which connects with a tuningfork. As a tuning-fork can produce only a simple sound, that is, a sound of one pitch, so if the sounding body gives forth any sounds identical with those made by the forks, the latter will reproduce them. In his investigations on this subject, Prof. Mayer was led to observe that the antennæ of insects vibrate to sound, and subsequent experiments indicated very thoroughly that these are their organs of hearing. Mr. John Cottrell, F.R.S., has clearly demonstrated the power of heat to reflect sound. Waves of sound issuing from an aperture in a box were thrown at will into a similar aperture of another box, and otherwise turned aside by placing a jet of flame in different positions before the aperture.

The observations of M. Révy, of the Institute of Civil Engineers, Vienna, on the great rivers of Parana and Uruguay in South America, promise to greatly advance the science of hydraulics. They indicate that the velocity of a river is proportionate to its depth, diminishing or increasing therewith ; that the greatest velocity is at the surface and the least at the bottom, and that the increase of velocity is in the simple ratio of the distance from the bottom. If these conclusions are verified, they will also give new impetus to meteorology by affording means of determining constants of evaporation.

It has been shown by Thompson, on the one hand, that the affinity of hydrogen for the first member of each of the four natural groups of non-metallic elements is positive, but diminishes with the higher members as their atomic weights increase;, and, on the other hand, that the total heat of formation of sulphur acids decreases with every additional atom of sulphur. Berthelot has confirmed the view that when salts react upon each other in solution, the stronger acid seeks the stronger base, and vice versa. Dr. Draper has shown, contrary to prevalent views, that all rays of the sun, visible and invisible, have actinic power, that is, are capable of producing chemical change. Donkin, by the action of induced electricity on nitrogen and hydrogen mixed in proper proportions, has succeeded in producing ammonia, though only in small quantities.

In organic chemistry, Jungfleisch has succeeded in producing

by subjecting a mixture of carbonic oxide and hydrogen to the action of electricity; while, by similarly treating carbonic acid and hydrogen, he produced formic acid. A new coloring matter, anthra purpurine, has been obtained in the manufacture of olizarine.

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