BRA 



BRE 



species can be unrolled to a considerable 

 length, and protruded to some distance, 

 in search of aliment. See Palliohran- 

 chiata. 



BRACHFSTOCHRONE {/3pdxt<rroi, 

 shortest, xpovo?, time). The name given 

 by Bernouilli to a particular curve, by 

 which a body arrives at a given point in 

 a shorter time than if it followed any other 

 direction. 



BRA'CHIUM. The arm. The second 

 segment of the anterior extremity of the 

 lower mammalia. The brachia of insects 

 are the first pair of legs in the hexapods, 

 the direction of which is usually towards 

 the head. 



BRACHY'PTEROUS (/Jpax^r, short, 

 TTTepov, a wing). A term applied to birds 

 whose folded wings do not reach the base 

 of the tail. 



BRACHYU'RA (/3pax^?, short, ovpa, 

 a tail). A family of Decapods, distin- 

 guished by the shortness of the tail, as 

 in the common crab. 



BRACT {bractea, a thin leaf or plate 

 of any metal). A term applied to the 

 flower-leaf, or that leaf from whose axil 

 the flower-bud is developed. These are 

 the leaves which composse the involu- 

 crum of the Compositae, the glumes of 

 Grarainaceae, the spathe of Araceae, &c. 

 But the term is extended to all those 

 modifications of leaves which are found 

 upon the inflorescence, and are situated 

 between the true leaves and the calyx of 

 the flower. These are termed by some 

 writers bracteolce, or bractlets. 



BRA'NCA'S WHEEL. A machine 

 contrived by Giovanni Branca, in 1629, 

 for raising water, and other purposes. 

 It consists of a wheel furnished with flat 

 vanes around its circumference, like the 

 boards of a paddle-wheel. Upon these 

 vanes steam is propelled from a close 

 vessel; a rotatory motion is thus pro- 

 duced, and communicated to appropriate 

 machinery. 



BRA'NCHIA ifipajx^a). GUIs, or 

 respiratory organs which extract the 

 oxygen from air contained in water. 



BRANCHIOTODA {/Spdyxia, gills, 

 TTow, TTodof!, 3, foot). A dcsignatiou of 

 those Crustacea which have the branchiae 

 attached to numerous pairs of similar 

 feet. They possess mandibles and max- 

 illae, and are generally small, monoculous 

 or binoculous animals, with a large cara- 

 pace enveloping the whole body. 



BRANCHIO'STEGI {/Spdyx^a, gills, 

 cTeyco, to cover). A tribe of cartila- 

 ginous fishes, in which the gills are free 

 61 



and covered by a membrane, as in the 

 sturgeon. 



BRAND or BURN. A disease in 

 plants by which their leaves and tender 

 bark are partially destroyed, as if they 

 had been burned. 



BRASQUE. A term used by the 

 French metallurgists to denote the lining 

 of a crucible or a furnace with charcoal. 



BRASS. An alloy consisting of three 

 parts of copper and one of zinc. 



BRAZIL CURRENT. A branch of 

 the great Equatorial Current, separating 

 from the equatorial at 8° S. lat., opposite 

 Cape St. Augustin, running to the south- 

 west along the shores of Brazil to the 

 mouth of the Plata river, and traced to 

 the Straits of Magalhaens and Le Maire. 

 See Guiana Current. 



BRAZIL WOOD. The wood of the 

 CcBsalpinia Braziliensis, which yields a 

 red colouring matter used by dyers. 



BRAZILETTO. An inferior species 

 of Brazil wood, brought from Jamaica. 

 It is one of the cheapest and least es- 

 teemed of the red-dye woods. 



BRE'CCIA. An Italian term signify- 

 ing an opening or breaking in any sub- 

 stance, applied by mineralogists to those 

 compound stones which consist of agglu- 

 tinated fragments of considerable size. 

 When the agglutinated parts are rounded, 

 the stone is called pudding-stone. Ac- 

 cording to the nature of their component 

 parts, breccias are called calcareous, sili- 

 cious, &c. 



BREEZE, SEA and LAND. Names 

 given to winds of a very limited range, 

 experienced on the coasts of tropical 

 countries, and depending on local cir- 

 cumstances. 



1. Sea breeze. From its low conduct- 

 ing power, the surface of the land is 

 more quickly heated than the sea, so 

 that soon after sunrise the expanded air 

 over the former begins to ascend, and is 

 replaced by the colder air from the sea, 

 forming the sea breeze. 



2. Land breeze. After sunset, the 

 earth's heat, being diminished, is more 

 quickly dissipated by radiation than that 

 of the sea,, and the air over the land 

 becomes dense and flows outwards, dis- 

 placing the air over the sea, and pro- 

 ducing the land breeze. 



BRENTl'DES. A family of Coleo- 

 pterous insects, named from the genus 

 Brentus, and belong to the section Rhyn- 

 cophora and sub-section Recticornes. 



BRE'VIPENNES {brevis, shoxt, penna, 

 a quill). Short-quilled; a designation 



