especially those of the begging friars. Manuscripts and BLOCKBOOKS (q.v.). Bibliography. Science, or, in narrower bounds, classification, of printed books and pamphlets. It has three subdivisions: Universal, National, Special. It is distinct from the study of manuscripts, inscriptions, and the like, dealing exclusively with the product of the printing-press. To use a commercial term, it does the bookkeeping for the great business of literature. It began 1545 with Gessner's Bibliotheca Universalis. In recent times the U. S. can boast of great activity in this department, which is daily growing in importance, and is fostered by the necessities and expansion of our great libraries, as well as by the spread of individual scholarship.

Bibliomancy. Divination by regarding as a special and personal message the first words seen on opening a Bible at random, or heard on entering a place where it is being read; custom forbidden 465, but long prevalent. Other books, especially Virgil, were anciently used likewise.

Bibliomania. Inordinate zeal in collecting rare or peculiar books, or paying enormous prices for them.

Bicêtre. Castle and fort s. of Paris; used as a prison till 1837, now as a hospital and lunatic asylum.

Anatomist

Bichat, MARIE-FRANCOIS-XAVIER, 1711-1802. and physiologist. Récherches Physiologique sur la Vie et sur la Mort; Anatomie Descriptive.

Bichromates. Salts derived from an acid of the composition H,Cr,O,; e.g., K,Cr,O, potassium bichromate.

Bickerstaff, ISAAC, ab.1735-ab.1788. Irish author of comedies and farces.-Name assumed by SIR R. STEELE in The Tatler. Bickersteth, EDWARD, 1786-1850. English divine and popular author; sec. Ch. Missionary Society 1816-30, and active in founding the Evangelical Alliance, 1845.-His son, EDWARD HENRY, D.D., b. 1825, Bp. of Exeter 1885, has written many hymns and poems, besides the most popular recent English epic, Yesterday, To-day, and Forever, 1866.

Bicocca. N. Italy; scene of a defeat of the French by the Imperialists, April 29, 1522.

Bi Compounds. See DI COMPOUNDS. Bicuspid Teeth. Fourth permanent tooth, counting backward from the middle line, on each side of both jaws.

Bicycle. In 1815 the bicycle was first brought into England from France, consisting of two clumsy wooden wheels joined together by a wooden bar, astride which the rider sat and propelled himself by striking the ground with first one foot then the other. No real progress was apparent in the bicycle for the next fifty years, until in 1869 M. Michaux, of Paris, conceived the idea of making the driving-wheel much larger than the other. Shortly after M. Magee, also of Paris. developed the manufacture of the parts in steel and iron. From that time progress was more rapid. At about the same time, it is some

Ordinary Bicycle, 1879.

times claimed in 1865, Pierre Lallemont constructed a roadworthy bicycle, at Ansonia, Conn. But American bicycling dates from ten years later, when Col. Pope of Boston and Harrington of England made and rode a bicycle of modern construction. The high-wheel soon gave way to the safety, or

171

The line of latest development has been in the tires, the original metal tire being replaced, first by solid rubber and later by pneumatic tires, rubber tubes filled with air. The rims also have progressed in the point of increased lightness from heavy metal to lighter metals and finally wood. The old high wheel weighed 50 lbs., the modern safety is often under 25, and racing wheels as low as 15 lbs. The increase of the use of bicycles in U. S. is shown by the fact that in 1885 there were 6 manufactories, with an output of 11,000 wheels; in 1890, 17, producing 40,000; while in 1895 there are 126, with a probable output of 500,000 machines. This will undoubtedly tend to develop better roads throughout the country. The speed attained is something remarkable, as the following records show up to 1895.

The "Ordinary," Mile Records:

3.11

W. W. Stall.

Sandy Sellers.

Richard Howell. G. M. Hendee. W. A. Rowe.

W. W. Windle. W. F. Murphy.

1881

G. M. Hendee.

G. M. Hendee.

F. J. Osmond.

2.25

Sept. 1890

W. W. Windle.

Richard Howell.
A. P. Englehart.
S. G. Whittaker.
W. C. Jones.
F. J. Osmond.
W. W. Windle.
Geo. F. Taylor.
H. C. Tyler.
W. W. Windle.
H. C. Tyler.

J. P. Bliss.

H. C. Tyler.

Paced Records. The favorite and most approved method of enabling a rider to make his best time on the bicycle is to have another rider (or even two upon a "tandem" machine) take the lead and keep just ahead of the record-man, being replaced at certain points by fresh men. Such records are called" paced" records."

Records of Flying Start and Paced (up to 1895):

t-m.

-m.

-m.

-m.

-m.

-m.

2-m.

5-m.

10-m.

20-m.

25-m.

50-m.

100-m.

300-m.

23 s., Johnson, Nov. 5, '94. 32 s.,

66

66

66

Sept. 21, '94.

1m. 21 s., Tyler, Oct. 27, '94.

1m. 47 s., Johnson, Nov. 21, '94. 3m. 54 s.,

66

Longer distance records are as follows:

66

10m. 22 s., Johnson, Nov. 17, '94. 22m. 45 s., Titus, Sept. 13, '94. 45m. 08 s.,

56m. 04 s.,

66

66

2h. 11m. 06 s., Meintjes, Aug. 13, '93. 4h. 37m. 56 s., Harding, Oct. 24, '94. 18h. 23m. 15 s., Gimm, Oct. 15, '94. Tandem Mile Record (up to 1895; bicycle with two riders): 1m. 52s., Haggerty, Williams, Oct. 27, 94.

Quadruplet Mile Road Record (bicycle with four riders): 1m. 41s., Rhodes, Callahan, Seavey and O'Connor, Oct. 23, '94. Bicycle Railway. Proposed system in which locomo

zontal wheels lightly press. It is claimed that the system will result in great economy of construction. In 1891 a short trial section of such a railway was built near Coney Island, N. Y.

Bicyclers. These riders have the same legal rights on highways as drivers of other vehicles, in the absence of statutory modification.

Biddeford. City of York co., Me., on Saco R. It has manufactures of cotton and lumber. Pop., 1890, 14,443. Bidding Prayer. In Greek, Anglican, and other liturgies; now nearly obsolete.

Biddle, NICHOLAS, LL.D., 1786-1844. Pres. U. S. Bank 182336, and of another so called 1837-41; pres. also of the trustees of the fund to found Girard College.

Bielids. Meteoric swarm, the constituents of which are believed to be fragments of Biela's lost comet. The earth encounters this stream in November; the radient is in the constellation Andromeda.

Biennial. Vegetable structures enduring for two seasons, as the fleshy roots of carrots and turnips.

Bienville, JEAN BAPTISTE LEMOINE DE, 1680-1768. French Gov. of La.; founder of New Orleans, 1718.

Bierstadt, ALBERT, b. 1830. German-American painter, noted especially for his pictures of the Rocky Mountains.

Bifilav Suspension. If a rod AB be suspended by two parallel cords and then rotated through an angle about a point half-way between the cords, it will be lifted slightly and a com. ponent of its weight will be developed which will tend to re. store it to its former position. It can be shown that the mo. ment of this restoring force is proportional to sin. and thus if e be small the oscillations of such a system will be approximately simple harmonic. This suspension is used in some forms of electrometers, magnetometers, and galvanometers.

Biforines. Raphides-bearing cells of Caladium, and other

aroids.

Bifrost. In Norse mythology, the bright Asa-bridge which leads to the underworld; the rainbow.

Biga. Two-horse chariot anciently employed in war; much depicted in marble or bronze as architectural ornaments.

Biga.

Bigamy. The marriage of one, who has a living spouse, with another. An ecclesiastical offense only, until 1603, when made a statutory crime. Honest belief of the spouse's death is not generally a defense.

Big Black River, Mo., BATTLE OF. May 17, 1863. Unionists captured garrison and stores.

Bigelow, FRANK HAGAR, b. 1851. Prof. in U. S. Weather Bureau 1891; author of Studies on the Solar Corona and its Relation to Terrestrial Meteorology and Magnetism.

Bigelow, JACOB, 1787-1879. Prof. Harvard 1815-55. Flor Bostoniensis, 1814-40; Am. Medical Botany, 1817-21.

Bigelow, JOHN, LL.D., b. 1817. Ed. N. Y. Post 1849-61; U. S. Consul at Paris 1861-65; minister to France 1865-6; ed. Franklin and S. J. Tilden. France, 1871; Molinos, 182; Life of Bryant, 1890.-His son, POULTNEY, has pub. books of travel.

Bigsby, JOHN JEREMIAH, 1792-1881. English geologist. author of Thesaurus Siluricus, a list of described Silurian fossils, and of Thesaurus Devonico-Carboniferus, 1878.

Big Sioux River. Left branch of the Missouri, forming the boundary between Iowa and Dakota. Length 210 m., drainage area 7,880 sq. m.

Bihari-Lal. Hindi poet of 16th century. Gilchrist called him the Thomson of the Hindoos.

Bikelas, DEMETRIOS, b. 1835. Greek poet, novelist, and tr. of Shakespeare. Greece in the Middle Ages, 1878; Loukis Laras, 1879; Tales from the Egean, tr. 1894.

Bilabiate. See LABIATE.

Bilateral Lithotomy. Operation for removal of stone in the bladder, in which the incision extends across the perinæum and close to the anus.

Bilateral Symmetry. Case when an organism can be cut into two portions which are counterparts but not mutually interchangeable, like the right and left halves of the body. See PROMORPHOLOGY.

Bilbao. Town of n. Spain, on the Nervion, 6 m. from Bay of Biscay; founded 1300. Iron ore is largely exported. Pop., 1887, 50,772.

Bilberry. Several species of Vaccinium, shrubs of the Heath family; especially V. uliginosum, of the northern hemisphere.

Bilbouquet (BALL-BOUQUET). Cup and ball, a favorite amusement of Henry III. of France and his courtiers. It came into fashion again under Louis XV., and its popularity was still great at the Revolution.

Bilderdijk, WILLEM, 1756-1831. Dutch poet and philologist. His wife, KATHARINA WILHELMINA, 1777-1830, was a poet.

Bile. Clear, tenacious alkaline fluid secreted by the liver, ranging in color from reddish-brown to a bright green, the lat ter in man. It is secreted by the liver and is poured out into the intestines at all times, but in the largest quantities immetions, but it assists somewhat in the digestion of fats and starchy

173

Bilge Water. Water which lies on the floor of a ship and cannot reach the pump-well, where it would be removed.

Bilious Colic. Extreme pain in the left side in the vicinity of the liver, caused by the passage of the gall stones from the gall bladder into the intestines, which are so large that the bile-duct is stretched violently by them. It is apt to recur, and can be relieved only temporarily by the use of opiates and

anæsthetics.

Bilious Fever. Vague term for any fever in which there is vomiting of bile or a yellowish coloration of the skin. The most common condition so named is an acute indigestion with slight fever and vomiting of bile, the latter a mere accident which will always occur whenever vomiting is violent and prolonged. It is also applied to remittent fever, especially when the skin is of a yellowish hue.

Biliousness. Condition in which there is more or less disturbance of the digestion, loss of appetite, headache and constipation, incorrectly referred to an excess of bile, but due to improper food, irregular living, lack of exercise, and neglect of the bowels, all which tend to set up a disordered condition of the stomach and intestines. Attention to the diet, exercise, etc., usually prove effectual in curing it.

In 1873 the first tournament of this game took place in the U. S. In 1883 the balk line game was introduced, a line being drawn 8 ins. from the cushions, inside which only two successive shots could be made. This was succeeded in 1885 by the 14-in. balk line. The cushion carom is a still more difficult game. The pocket table is now used in the U. S. only for pool, size 5 ft. by 10 ft., and 6 pockets; the following games are played: Bottle, Chicago, Continuous, Fifteen-ball, High-lowJack, Pin, Plant, and Pyramid pool.

Billiard records in match ganies, 5 by 10 table. In three-ball straight rail, highest run 1,531, by Vignaux against Slosson, 1889, Paris. Best average 3331. Schaefer, 1879, Chicago. On 4 by 9 table. the highest run 3,000, by Schaefer, 1890, San Francisco. His average was 700. Champions game, triangular corner lines, 18 by 38 ins., 5 by 10 table, highest run 398, and average 3839, by Slosson against Vignaux, 3.000 points up, 1882, Paris. Balk line game, 5 by 10 table, 8-in. line, highest run 329, average 44, Vignaux, 1884. Paris. Fourteen-inch line, anchor nurse, 566. Schaefer, 1893. New York; Schaefer and Ives each made average 100, 1894, Chicago. Anchor nurse barred. 350, Cushion caroms, 5 by 10 table, highest run 77. Sexton against Ives, 1894, Chicago; highest average 63, Ives, 1894, N. Y. Schaefer, 1881, N. Y.; highest average 10 in 200, Schaefer, 1887,

ment of their funds.

Bill in Equity. Statement of a litigant's claim addressed to an equity tribunal. If it initiates a litigation it is original; if used to amend, supplement, or continue a proceeding, or to controvert or suspend an order or decree, or for cross-litigation, it is not original.

Billing, HERMANN, d. 973. Markgraf in Saxony; duke

953-61.

Billet. In mediæval architecture, a decorative molding composed of projecting cylinders arranged at regular intervals.

Billiards. This game was a development of the game of bowls, played upon a table, with a protecting ledge, a ball being pushed with a wooden rod called a mast, now mace, and driven into a pocket after striking another ball. It is claimed to have originated in the East, and to have been brought west by the Knight Templars on their return from the first crusade. During the reign of Louis XI. it was played in France, and Henry III. called it "the noble game." The Elizabethan writers mention it. In 1674 the bed of the table was made of oak or marble, slate beds being used in 1827. The cushions were first of cloth. stuffed, later of felt. India-rubber cushions were used in 1835, and about 1865 cushions of vulcanized rubber were introduced. The pockets were boxes at first, being succeeded by nets. The mace was replaced by the cue in 1734, and in 1807 the leather tip was added to this by the Frenchman Mingaud.

In England at the beginning of the 18th century the tables were square with three pockets on one side only. A small arch was placed in the middle of the table, and near by a cone called the King. At intervals the player had to put his ball through the arch and round the King without upsetting either. Two balls were used, pocketing the adversary's ball counting one, and pocketing your own losing one point, the game 3 or 5. In French billiards. 1734, also called 'Doublet," the King and arch were not used, there was a pocket in each corner and one midway on the long sides of the table. The cue ball had to take a cushion before pocketing the object ball, or the latter was forced to the cushion before entering the pocket. In 1775 the French carom game appeared, a third ball being added, the carom consisting in striking the other two balls with the cue ball. Pockets were also counted as in the two ball game. In England the tables are 12 ft. by 6 ft., covered with green cloth, with rubber cushions, 6 netted pockets and 3 ivory balls 2 diameter. The game is 50 points and the counts as follows: holing the white, or the cue ball off the white, 2, the red, or the cue ball off the red, 3, a carom 2; if the player misses the object ball, the opponent counts 1, and if in the same shot his ball is holed his adversary counts 3.

in.

In America the tables were like the English tables. 4 balls were used 2 in. diam., and the game 100 points. The counts were 3 for a red pocket or a carom on two red balls; 2 for a white pocket or a carom on red and white; the opponent scores 1 for a miss, 2 for holing the cue ball off the white, 3 for holing off the red, and 3 for holing after a miss shot.

174

tion the States are prohibited from issuing bills of credit; still, corporations chartered by the State may issue them. This was a favorite mode of obtaining funds by many of the colonies. Mass. led in the movement 1690. Many issues were made by Pa. On some occasions the amount of bills issued was so large that they greatly depreciated, and were redeemed at their depreciated value. The common mode of redeeming them was by the way of taxation, the taxpayers having a right to pay all or a fixed portion of their taxes in such notes, which were then destroyed. Paper issues of a bank owned by a State are not deemed bills of credit within the prohibition of the U. S. Con

stitution, as the bank is liable to suit on them.

Bill of Exceptions. Written statement setting forth the objections taken to judicial rulings during the trial of a cause, duly authenticated by judge or court, prepared for the purpose of presenting the alleged error to the proper tribunal for

review.

Bill of Exchange. Unconditional order in writing by one person on another to pay to a third on demand or at a fixed or determinable future time a certain sum of money. When payable to order or bearer it is negotiable; its legal title is transferable by indorsement, or, if payable to bearer, by delivery, so that the transferer who takes it before due, for value and without notice of any defects, can enforce it in his own name, free from equities. If the person upon whom it is drawn accepts it, which is usually done by writing his name across the face, he is primarily liable. If he refuses to accept, the holder may treat it as dishonored and proceed at once against the drawer of the bill. Upon dishonor, whether by refusal to accept or to pay, the holder should give notice thereof to the drawer and indorsers, and if it is a foreign bill should have it duly protested. Such bills are said to have been invented by Jews ab. 1150, and used in England ab. 1300. De Paw says they were known at Athens and among the Arabs, but Boeckh affirms that exchange was unknown at Athens. The Abbé Raynal says the Portuguese found them in use in the East Indies ab. 1500.

Bill of Lading. Written receipt of goods and contract for their transportation by a common carrier. It is a symbol of the goods, and its indorsement and transfer operate a constructive delivery of the property. The innocent transferer for value takes them freed from the right of stoppage in transitu; but he is subject to equities generally, as a bill of lading is not fully negotiable.

Bimana. See ANTHROPIDE.

silver, at a fixed ratio of value, are full legal tender, and are Bimetallism. Monetary system in which both gold and both coined on equal terms at the national mints. Its theory is that if the legal valuation does not always correspond with that of the market the tendency will be to make payments in the cheaper metal, thereby increasing its use and value and diminishing those of the other. The two metals circulated at a relation of 15, 15, or 16 to 1, in the leading commercial countries of the world for a long period. In 1870 the German government determined to adopt a gold standard, as England had done in 1816. A large amount of silver was thrown on the market, and at the same time silver mines of extraordinary richness were discovered in the U. S. The effect of the action of Germany and of the largely increased supply from mines was to lessen greatly the market value of silver. At once a fresh agitation began for demonetizing the use of silver. One reason for this was that the world possessed gold enough for the money of the world, and therefore silver could be discarded without any detriment to business. The market value continued to decline, but the bimetallists believed that as the value of gold and silver depended largely on their use for monetary purposes, if the leading nations of the world could be perthe value of silver could thereby be preserved. Several conferences, held for this purpose, were failures.

suaded to continue to use the two metals at a fixed relation,

Binary. Numbers in two figures; scales with two as a constant ratio; combination by twos.

Binary Fission. Usual method of cell division, in which complete individuality and similarity to its parent cell. a cell simply splits into two halves, each assuming at once a

Binary Quantic. Algebraic expression containing two (and only two) variables.

Binary Stars. Double stars which revolve together about a common center of gravity, as the earth revolves about the sun. Ab. 200 examples are now known.

ether or of the carbon disulphide (CS,) in a second cylinder beBinary Vapor Engine. One which used the vapor of hind the primary steam cylinder. Name specially given 1847 to an engine of Du Trembley, and 1872 to that of J. H. Ellis, but applicable also to engines in which the carbon vapor is mixed with the steam. The advantage sought lies in the lower vaporizing point of the carbon vapor as compared with water; DISULPHIDE ENGINE.

Bill of Particulars. Specification of the facts making up the claim set forth in a litigant's pleading.

Bill of Peace. Equity bill, generally brought after adverse legal proceedings have been instituted, to secure a decision which relieves complainant from multifarious or useless

suits.

Bill of Rights. Granted by Charles I. of England, June 7, 1628, in answer to the Petition of Rights presented March 16. Also statutory declaration of English popular rights at the accession of William and Mary, Feb. 13, 1689. Also, constitųtional provisions in the U. S. for securing personal liberty; sometimes called Declaration of Rights.

Bill of Sale. Written agreement evidencing the absolute transfer of personal property; if sealed, neither consideration nor delivery was necessary at common law to pass title, as against the seller, though his defrauded creditors might recover the property.

Billon. Subsidiary coinage of a country, of less intrinsic value than their proportionate part of the standard would indicate, and not legal tender except for limited amounts. German minor coins, till recently, were alloys of copper and silver; in most Roman denarii after ab. 220 copper washed over with silver.

Bilophodont. Teeth whose crowns are traversed by two transverse oblique ridges, separated by shallow valleys, as in Tapirs.

Bilson, THOMAS. D.D., 1547-1616. Bp. of Worcester 1596, and Winchester 1597. Subjection and Rebellion, 1585; Government of Christ's Ch., 1593.

Bilsted. Liquidambar Styraciflua. Large e. American tree of the Witch-hazel family, known also as Sweet-gum and Ling.

Bindweed, BRACTED. Convolvulus sepium. Vine of the Morning-Glory family, native of the northern hemisphere, called also Hedge Bindweed.

Bingham, JOSEPH, 1668-1723. Anglican divine, whose Origines Ecclesiastice, 10 vols., 1708-22, is still the standard work on Church antiquities.

Binghamton. City of Broome co., N. Y., at junction of Chenango and Susquehanna rivers; settled 1787. Pop., 1890, 35,005.

Binney, HORACE, LL.D., 1780-1875. Phila. lawyer, M. C. 1833-35. Formation of Washington's Farewell Address, 1859. Binney, THOMAS, D.D., LL.D., 1798-1874. Cong. pastor in London 1829-71.

Binocular Vision. Faculty by which an object is seen by both eyes and blended into one perception; dependent upon the fact that when the visual axes of both eyes are directed toward a body its image falls upon corresponding points in the two retinas. When the axes have not the same direction, a double image is the result.

Binomial. Algebraic expression of the sum or difference of two dissimilar quantities. The difference is sometimes called a residual.

Binomial Differential. A function of one variable in the form:

x"(a+bxm)Pdx.

Binomial Equation. Having one variable and one absolute term, and reducible to the form xa-o.

Binomial Nomenclature. In biology, designation of each species of organisms by the generic as well as the specific term. In botany, the former always begins with a capital, the latter only when derived from a word usually so written.-In zoology it is now usual to write the specific word with a small letter; e.g., Dendroica auduboni, Audubon's Warbler.

175

Huxley that the word became popularized. It is now frequently used, first, when both plants and animals are alone included; second, when the ecological relations, and the general phenomena which form the subject matter of Darwin's investigations, are referred to; thirdly (but now in disrepute), in a mystical sense. referring to a life principle, or biomagnetism. The history of biology previous to the times of Lamarck, Oken, Buffon, Geoffroy, etc., whose speculations are now termed "biological," is that of Botany, Zoology, and Physiology respectively. Even the later investigations and works of Darwin, Huxley, Spencer, Wallace, etc., are treated historically more usually in works of Zoology. The old term Natural History corresponds nearly to the general meaning of Biology. Huxley points out that both Psychology and Sociology are intimately related to Biology, and may properly be considered as branches of it. In addition to Morphology and Physiology he distinguishes Distribution (bathymetric, geographic, and paleontologic) and Etiology as coordinate divisions. Biology is therefore a vast complex of sciences, equivalent in extent to all the non-biological or "physical" sciences on the one hand, and the so-called "humanity-studies" (Philology, Philosophy, Art, History, etc.) on the other. Its proper subject-study is the interaction of "life." "mind," or "soul," and "material forces," in organisms. From the biological standpoint a new and practical classification of the sciences becomes possible. The study of this group is evidently needed for any adequate conception of Philosophy or of Nature. This study is transforming all previous conceptions of life in the individual, in history, and in nations. See CELLULAR BIOLOGY.

Bion, ab. 280 B.C. Greek idyllic poet, perhaps master of Moschus, b. at Smyrna and resident in Sicily; praised for invention and elegance of versification. His most famous poem is the Lament for Adonis.

Bion. The "physiological" individual. This may consist (1) of a single plastid, or (2) of a cytocormus which has become integrated into a gastrula or phytula, or (3) of a colony of gastrulas (or phytulas, etc.) or polypocormus, which has become integrated into a prosopen, or (4) of a colony of prosopens which has become integrated into a deme. The chain Salpa or a Pyrosoma represents stages of the integration of a prosopocormus into a deme. See MORPHON and PROMORPHOLOGY.

Bioplasm. See PROTOPLASM.

Biorgan. Any segregation of plastides and tissues that acts as a part of a mechanism in a living organism; distinguished from IDORGAN (q.v.), e.g., heart, spleen, kidney.

Biot, JEAN BAPTISTE, 1774-1862. French mathematician and physicist, prof. Coll. of France 1800, academician 1803. With Arago he measured the arc of the meridian. Analytic Treatise on Curves, 1802; Physical Astronomy, 1805-57; Experimental Physics and Mathematics, 1816; Ancient Astronomy, 1829.

Biot's Hypothesis. Supposition that the magnetic field of the earth is due to a magnet passing through its center, short in comparison with the radius and making an angle of about 20° with the earth's axis of rotation. The actual phenomena observed, however, are much more complicated than the results to which this hypothesis leads.

Biot's Laws. In Optics; deduced for the rotation of the plane of polarization of a plane polarized beam of light: (1) The amount of rotation is proportional to the thickness traversed by the ray. (2) The rotation effected by two plates is the algebraic sum of the rotations produced by each separately. (3) The rotation augments with the refrangibility of the light, and is

n(n-1)

n(n-1)(n-2)

If "n" be a positive integer the series is finite, having (n+1) terms: otherwise it is infinite. The theorem is true for all values of n, but develops (a+x) only when a > x numerically. Biogenesis. Origin of organisms from pre-existing ones, as distinguished from abiogenesis, or spontaneous generation. Biography. History of individuals; department of literature important from the times of Xenophon and Plutarch, and now cultivated more diligently than ever before. Biog. dictionaries, which in our time have assumed such size and prominence, began with Torrentinus 1498.

Biology. Science which studies the laws of the manifestations of life, without restriction to any particular aspects of life or kinds of living beings. For convenience it has been divided into Zoology and Botany, and along similar lines each of these has been subdivided according to the classification or grouping of the organisms studied. A more philosophical analysis of the subject is into Morphology and Physiology. The term was first used by Lamarck 1802, although Treviranus had used it previously, unknown to the former. It was not before Darwin and

length.

Bipinnaria. Larva of the Starfish. It has short, lobelike arms, is bilaterally symmetrical, has no skeleton, and has a circle of cilia around the mouth-end.

Biprism. Glass prism having a very obtuse angle, used for studying the phenomenon of light interference; hence often pendicularly on the opposite flat face, it will be divided at called interference prism. If a beam of light be incident peremergence into two beams slightly inclined and in the best condition for interference, having proceeded really from a common origin. It is found under these circumstances that a series of alternate bright and dark bands is formed parallel to the edge of the prism. Sometimes known as Ohm's prism.

Euler to dependence upon a cubic, and thus a general solution Biquadratic Equation. Of the 4th degree, reduced by

obtained.

Biquartz. Plate of quartz, formed of two pieces, cut at right angles to the optic axis and placed in juxtaposition. One-half of the plate is dextrogyrate, the other lævogyrate. The thickness is the same for both haives, and usually so regulated that the rotation is 90° for yellow light.

Birch. Trees and shrubs of genus Betula, of natural family