BIONOMICS. organisms to the chemical nature of the water, to its density, to its volume, to its tempera- ture and currents, to light, and to gravity; the relations of land animals to the humid- ity and temperature of the air, to the other chemical and physical properties of the me- dium, to light, to' gravity, and to air-currents; the relation of organisms to alternate submer- gence and desiccation; their relation to shel- ter and homes: the relation of animals to their organic environment; their relation to food, to mates, to the nutrition and care of young, or to enemies; animal comnumities ; and the inter- dependence of organic species, as in parasitism and commensalisni or symbiosis. Most of these topics are separately treated elsewhere. Consult
aether, Einhitung in rfic f/co?o,f;i>. Parts I.II.;
liionomie der ileercsthiere and Lebensweise der Mccresthiere. See Ecology. BION'OMY. See Paleontology; Ecology; DiSTRiuiTio.N OF Animals; and of Plants. BIOT, be'6' or by6, Edouahd Constantin (1803-50). A French writer on China. He was born in Paris. .July 2, 1803, and was a son of the astronomer J. B.Biot. After a short ser- vice in railway enterprises, he devoted himself to the study of Chinese and contributed many valuable papers to the Journal Asiutique. He jireparcd a Dictinnnairc dcs villcs et arrondisse- mciits dc Veminre chinois (1842) ; and he wrote De I'abolition dc I'csclavagc ancien en Occident (1840), for which he received a gold medal from the Institute. He became a member of the Acad- emy in 1847, and died March 12, 1850, his love of work having shortened his days. BIOT, Jean Baptiste (1774-1862). A dis- tinguislied French physicist and astronomer. He was born in Paris and early entered the artil- lery, but forsoolv the army for science. He was appointed a professor of mathematics at the Ecole Centrale of the Department of the Oise and in 1800 became professor of physics in the College de France. He was made a member of the Institute in 1803; and in 1804, at a meeting of that body called to vote in favor of establish- ing an enqiire, Biot refused to vote. With Arago he was made a member of the bureau of longi- tude, and (1800) sent to Spain to supervise the trianguhition involved in the measuring of an arc of meridian, preparatory to the introduction of the metric system of weights and nicasiires. He was active in geodetic work, visiting England in 1817 to make observations on an are of meridian then being measured. Together with Arago he also made an exact determination of the force of gravity in Paris, and they were associated in a number of scientific investigations. Biot wa.s able to demonstrate by direct experiment that the ve- locity of sound in solids was greater than in air, and was the founder of saecharimetry l)y the use of the polariscopc. He made many discoveries in optics and electricity, and was a constant con- tribitor to the scientific journals. In comi)any with (iay I.ussac. he made the iirst balloon ascent for the purpose of making scientific observations. His most valuable contributions to science deal with the polarization of light; and his researches connected with ancient astronomy are also very valuable. Of his numerous writings may be mentioned Trail 6 clfmentnire d'uxtronomic ph;/- f:i(iuc, 3 vols. (Paris, 1805) ; 3d cd., considerably augmented (18.50), 6 vols., with vol. of plates — 92 BIRCH. translated into English; Traits de physique, 4 vols. (1816) ; Precis de physique, an abridgment of the former in 2 vols. (1818), often repub- lished; Uccueil d'obsvrrutions (jfodesiques, etc. (1821). Biot also contributed many excellent biographies of scientific men to the liiographie Universelle. Among the most important of his later works arc Ifcchcrches sur piusicurs points de rastronomie egyptirnne ; liccherches sur I'ancienne astronomic chinoise (1840) ; Mimoire Siir la constitution dc rafmosphcrc Icrrcstre, in the Connaissiincc dcs temps (1841) ; .Melanges seicntifiqucs ct littiraircs (1858); and ICtudes sur I'astronomie ind.enne et sur I'astronomie chinoise (1862). BIPEN'NIS (Lat. bis, twice -f penna, wing, edge). A double-headed axe, a form of weapon found even in stone, known in Homer, and later usually attributed in use to barbarians, and espe- cially to the Amazons. BI'PONT EDITIONS (Bipontium is Latin translation of Ger. Zweibriicken ; from bis, twice + pons, bridge ) . A name given to a classical series of fifty volumes, begun at Zwei- brlicken (1770) and finished at Strassburg. BIQUADRATIC EQUATIONS (from Lat. bis, twice -|- quadrntus, squared). Equations- of the 4th degree in one unknown quantity. A function of the 4th degree is often called a quar- tic. If all positive integral powers lower than the 4th are also present, the equation is called a complete biquadratic. See Algebra; Equa- tion. BIR. See Bikejik. BIRAGO, be-rii'gA, Karl, Baron von (1792- 1845). An Austrian military engineer, born at Cascina d'Olmo, near Milan. In 1825 lie invented the military bridge named after him, con- sisting of detachable blocks and pontoons — an in- vention adopted by the Austrian Army in 1828. He erected the military bridge across the Po, at Brescello (1839), which was followed, a few years later, by a similar bridge across the Dan- ube. His system of constructing military bridges was adopted by nearly all the armies of Europe. He wrote: Untersuchungen iiber die curopiiisehcn ililitarbriickentrains, etc. (1839); and Anleitung zur Ausfiihrnng der im Felde am meisten rorkommendcn Pionicrarbeiten. BIRCH. Bctula, a genus of plants of the natural order lietulacece. The order contains two important genera, birch and alder, the plants of which are ail trees or shrubs, natives of tem- perate and cold regions. The genus Betula is distinguished by ton to twelve stamens, and winged achenia. The com- mon birch (lictula alba) has small, triangu- lar, d(mbly serrated leaves. It is a very beauti- ful forest tree, abounding in the north of Europe and of Asia, often forming large groves by itself. In the south of Eiinii)e it is fcmnd only upon mountains of considerable elevation. It is a tree of rapid growth. In favorable situations it at- tains the height of 60 or even 70 feet, with a diameter of P.; or 2 feet. In the northern, or ut- most alpine limits of vegetation, it only appears as a stunted bush. The bark is smooth and sil- very white, and its outermost layers are thrown off as the tree advances in age. The smaller branches are very slender and llexible, and in a particularly graceful variety called the weeping
