The Academy of Sciences at Paris has recently heard a report on certain explorations made in 1847-8-9 by M. Rochet d'Hericourt, a traveller in north-eastern Africa. This traveller has, by repeated observations, determined the latitude of Mt. Sinai to be 28° 33' 16", of Suez 29° 57' 58", of Devratabor 11° 51' 12", and of Gondar 12° 36' 1". Mt. Sinai is 1978 metres (about 6500 feet) high. Mt. Dieu 2174 metres (7200 feet), and the highest of the Horch Mountains 2477 metres (8100 feet). The Lake of Frana, south of Gondar, is 1750 metres (5700 feet) below the level of the sea, and its depth in one place is 197 metres (645 feet). Rar-Bonahite, the highest peak in Abyssinia, is 4330 metres (14,200 feet) high, but not high enough to have snow. The traveller describes a great variety of hot-springs, some of which contained living fish an inch long. The geology of Abyssinia he has thoroughly investigated. In the north, the principal rocks are granite and syenite. Among the plants he describes is a magnificent lobelia, almost large enough to be called a tree, which is found to the very summits of the mountains, and to a height which would not be supposed to admit of such a growth. He also finds the plant whose root has been found to be a specific against hydrophobia. Of this he brought back seeds, which have been planted in the Jardin des Plantes with success. A peculiar breed of sheep M. Rochet d'Hericourt thought worthy of being transferred to France, but of the pair he sent the female died on the route. This sheep has a very long and silky fleece. On the shores of Lake Frana he also found a very large sort of spiders, whose cocoons, he said, were converted into excellent silk. He thinks these spiders might be brought to Europe, and employed in producing silk, but in this he probably does not enough consider the difficulty, or rather the impossibility, of domesticating and feeding these insects.
Enormous fossil eggs were found a few weeks since subjects of curious discussion in Paris, and several notices were translated for the New-York papers. The eggs were discovered in Madagascar. M. Isodore Geoffrey St. Hilliare, in a recent report to the Academie des Sciences, furnished further details; and three eggs and some bones belonging to a gigantic bird, which have been presented to the Museum of Natural History in Paris, would seem to leave no room for doubt. Fairy tales are daily thrown into shade by the authentic records of science. This discovery appears to have been stumbled on curiously enough. The captain of a merchant vessel trading to Madagascar noticed one day a native who was using for domestic purposes a vase which much resembled an enormous egg, and on questioning him was informed that many such were to be found in the interior of the island. The largest of these eggs would hold two gallons. The volume equals that of 135 hen's eggs. Some doubts were at first entertained as to the nature of the animal to which the fossil bones belonged; but M. St Hilliare—a competent judge in such matters—has pronounced them to be those of a bird to which he has given the name of Epiornis.
The sum of £1000 has been placed by the British Government at the disposal of the Royal Institution, for scientific purposes.
In the Paris Academy of Sciences (first meeting in March), M. Leverrier submitted a communication from Mr. W. C. Bond, entitled Observations on the Comet of Faye, made at the Observatory of Cambridge, Massachusetts. Every thing is prized that comes from that quarter. M. Boussingault, the scientific agriculturist, read an extract from his memoir on the extraction of oxygen gas from atmospheric air. His undertaking was to extract, in a state of purity and in considerable quantity, the oxygen gas mixed with azote in atmospheric air, and he thinks that he has fully succeeded, by a process not attended with much difficulty. He details some unexpected results from his experiments. Cauchy made profound reports (from committees) respecting the Researches on Algebraic Functions by M. Puiseux, and the studies of Crystallography by M. Bravais. Papers on the speed of sound in iron, and on respiration in plants, and new schemes of atmospheric railroads were submitted. Attention was given to M. Burg's new observations concerning the advantageous use to be made of metallic bands in various nervous disorders in which the ordinary therapeutic expedients are found ineffectual. M. Peligot mentioned a memoir which he was soon to put forth as a sequel to the Researches on the nature and properties of the different Sugars, which he published in 1838. He has succeeded in extracting, by means of lime, the crystallizable sugar, in large quantity, contained in molasses. He got twenty-five per cent., by the agency of lime, carbonic acid, or sulphuric acid. Lime is cheap and harmless. Other circumstances recommend his series of experiments. A scientific reporter writes mysteriously of the discovery of a very simple and easy method of extracting sugar from the beet-root; with an apparatus which costs very little, any one may make his sugar with as much facility as he boils his pot.
Of the Expedition To Central Africa, we learn from the Athenæum that letters from Dr. Barth and Dr. Overweg have been received in London by Chevalier Bunsen, by which it appears that up to October last the travellers were still detained in the kingdom of Aïr. A previous communication gave an account of difficulties and dangers which they had met with on entering that country; the inhabitants of which had shown themselves hostile to them, so that their fate seemed entirely to depend on the protection of the Prince En-Nūr, sultan of the Kelvës. This hoped-for protection they have been fortunate enough to secure; though it appears not to have been sufficient to insure their safety beyond Tin-Tellus, the residence of the Prince, in consequence of which they have been obliged to forego the exploration of the country, and to remain with the Prince. They have however been enabled, while thus stationary, to collect a good deal of oral information,—especially respecting the tract of country to the west and southwest of Ghat: which, instead of being a monotonous desert, proves to be intersected by many fertile wadys with plenty of water. Among these novel features, not the least interesting is a lake, between Ghat and Tuat, infested with crocodiles. At the date of Dr. Barth's letter (2d of October) the travellers were on the point of setting out on an excursion to Aghades, the capital of Aïr; the new sultan having promised them his protection, and the valiant son-in-law of En-Nūr accompanying them on their journey. The latitude of Tin-Tellus has been found to be 18° 34' N.; the longitude has not been finally determined. The rainy season lasts till September, and thunder-storms occur daily in the afternoon between two and three o'clock, accompanied by a west wind, while at other times it blows from the east. It seems yet uncertain when the expedition will be able to start for lake Tchad.