�SCIENCE.
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— Bou(|iiel lie In Gryo is ordered by the Frencli mfnUtry of [nstrucliun Co proceed to TeiierifFe, in order to study the lavs of gravilatioii under all Ibe clrcutn stances tor which the Peak offers facilities.
— Dr. Pecbuel I^osche reports curious changes In the physical geography of Africa; "Lake Ngami It dried up; the gome haj died or gone away; the Tegetalion exists no longer; bolh the Okavango and the Tamnkau flow into the Zunbezl." Dr. Pechuel Losche returns to Europe with rich collections, in- cluding a living Welwitschla, perhaps a new species of that curious plant.
— Dr. Lenz will leave Vienna in May forlhe upper Kongo, whence he will endeavor to cross the old equatorial province of Egypt In order to eatabllsh relalioDB with Emir Buy and Lupton Bey's party.
— Dr. Silvers of Hamburg, who left that town in October, 1S84. on an exploring expedition lo the Cor- dillera of Murida in Venezuela, arrived at Tovar on Jan. B, and from there will commence his explora-
— The Simaphort de Marseille reports a method of sugar- manufacture which Is Ui supersede heet-root by potatoes, the saccharine matter being extracted by the help of el eel He I ty. Paris capitalists, and even Enelish, are reported to be interesled In the iiiven- tlon.
— The Marine biological association of England has already raised fIx thousand pounds of the fund required to found a station on the south coast of England, but requires four thousand pounds more befrire beginning to build. Ciimbridge has under- taken to raise five hundred pounds.
— A ccirrespoiident of the Oeslerreiehltche monaU- tebryt Jiir den oritnt writes, that If the reports of the few parties who have succeeded in gaining personal knowledge of the interior of the celestial empire did not agree In the fact that a kingdom of four hun- dred million inhabitants awaits the products of Eu- ropean factories, which will lie opened to ciimmerce bj the Introduction of modern means of intercourse, the beginning of the development of Enrupean in- dustries in Ihe Interior, as evidenced In the last few years, would awaken immediate and serious anxiety for the future of the English trade. Led by their position, Hong-Kong and Shanghai are setting a good example in this direction to the other places which come in contact with European civilization. Hong- Kong has al present three large sugar-refineries, a ipirlt-distillery, a cordage-mill supplied with modern machines, and an ice'factory. Bt^e1des these, there are lai^e glass and Iron works, and an arrack-distil- lery, In course of construction; while the Chinese carry on woollen and cinnabar works In great style and with modern improvements. In Shanghai, to the establishments which have existed for several years, there was added, a few months ago. a new one of considerable importance, — the paper-factory of the
��Shanghai paper-mllt company, which makes r< and medium fine papen out of rag«. This factory, established by Umpherston ■& Co. of Lelth, and quite up to time in lis plant, produces, on an average, two tons of paperaday; and later the production will be increased. It is under European direction, and em- ploys only Chinese workmen.
— With a view to effectually prosecute marine ilsh- culture on sound nclentlBc principles, the English national fisli-cuiture association has under considera- tion a sclieme for carrying out a series of observations on the temperature of the sea at various stages, In order to obtain a mora thorough and concise knowl- edge of lith, their habits, food, etc. Thermometers for this purpose will be distributed to those selected for observers under certain rules and regulations.
— From experiments carried on by the French com- mission for the sdentlGc study of firedamp, It Is found that the most violent explosion takes place when there are 13 parts of air to 100 of firedamp, and that above or below this the explosion dimlaishes In violence. When the mixture is below 7 parts In lOO, or above IS in 100, the gas simply burns with Its chai^ acterlstic blue flame. Tbe singing noise often beard in mines is asci-ibed to the escape of gas from many minute cavities; while It must exist in some places In vast quantities, as Is witnessed by its use for illu- minating-purposes.
— Prof. J. A. Ewingof University college, Dunde«, bas communicated apaper to the Royal society, which contains several points of Immediate practical ini- porlance. He finds, for example, that the ' dlsslpa^ tlon of energy ' by reversal of m^ietlsm is very much smaller in soft Iron than in hard iron or steel, and even in the latter its amount Is trifling; so that the principal part of the heat which is produced In the cores of electro- magnets must be due chiefly to other causes than Ihe ' static hysteresis,' or static lagging action observed by Professor Ewing, and Is, in fact, due almost wholly to the induction of so-called Foucault currants in the cores. The eEFects of tlils action are also almost entirety removable byvibrvt- iug a piece of soft iron during the application and removal of magnetizing force, and the Iron is then found to possess almost no re ten liven ess; but, when tbe application and removal of magnetizing force are effected without mechanical disturbance, the reten- tiveness of soft iron Is found to be even greater than that of steel. In some cases ninety-three per cent of the whole induced magnetism of a piece of annealed Iron was found to remain on the complete removal of the magnetizing force. Examples were given lo show that the influence of permanent set in the curve o( magnetism Is so marked as to give a criterion by which a strained piece may be readily distinguished from an annealed piece of metal; and that strain di- minishes very greatly the magnetic relenllvencss of Iron.
— Capt. Hoffmann of the German navy has pre- pared a valuable pamphlet on ocean-currents (Zur mecbanik der meeresstriimmigen an der oberflache aer oceane, Berlin, 1884), which gives a better
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