BAG 



B A L 



A'ZOTE (a pnv., ^wij, life). A gas 

 constituting 73 per cent, of the atmo- 

 sphere, and thus named from its being 

 incapable of supporting respiration. It 

 is more commonly called nitrogen, from 

 its being the basis of nitric acid. 



AZOTIC and AZO'TOUS ACIDS. 

 Names given by Thenard to the nitric 

 and the nitrous acids, respectively, of 

 other chemists. The latter acid was 

 termed hyponitrous by Turner. 



A'ZURE. A fine blue pigment, com- 

 monly called smalt, consisting of a ghiss 

 coloured with oxide of cobalt, and ground 

 to an impalpable powder. 



AZURE STONE. Lapis lazuli. An 

 azure blue mineral, from which ultra- 

 marine is prepared. 



A'ZURITE. Prismatic azure spar, or 

 Lazulite. A mineral occurring in mica 

 slate, and consisting of alumina, silica, 

 magnesia, lime, and oxide of iron. 



B 



B. in astronomical tables, stands for 

 Bissextile, or Leap-year. 



BA'BINGTONITE. A crystalline min- 

 eral, associated with cleavlandite, flesh- 

 coloured felspar, and green amphibole. 



BA'CCA. A berry ; an inferior, inde- 

 hiscent, pulpy fruit, as the gooseberry. 

 The seeds lose tlieir adhesion when ripe, 

 and lie loose in the pulp. The term is, 

 however, differently employed by some 

 botanical writers. Link applies the term 

 haC'^a sicca to a fruit which is fleshy when 

 unri])e, dry when ripe, and then distin- 

 guishable from the capsule by not being 

 brown. 



BA'CCATE {hacca, a berry). Berried ; 

 having a juicy succulent texture, as the 

 calyx of blitum. 



BACK STAFF. An instrument in- 

 vented by Capt. J Davis for taking the 

 sun's altitude at sea. In using it the 

 observer was oblijied to turn his back to 

 the sun. It is now superseded by the 

 quadrant and the sextant. 



BACONIAN PHILOSOPHY. A sys- 

 tem of philosophy founded on induction, 

 enforced by the talent and writings of 

 Francis Bacon, Lord Verulam. This sys- 

 tem holds an intermediate place between 

 the merely empirical and the dogmatical 

 schools. " While the one," he observes, 

 *'like ants, content themselve-i with 

 heaping up materials for immediate use, 

 the latter, after the manner of spiders, 

 spin webs out of their own brain. There 

 is a better and a middle way — that of the 

 bee, which derives, indeed, its material 

 from the flowers of the garden and the 

 field, but converts and digests it by its 

 own proper virtue." 



B.VCULITE {bnculus, a staff). An 

 extinct genus of Molluscous animals, 

 4G 



allied to the Nautilus, which inhabit a 

 str light-chambered shell resembling a 

 staff. 



BAI'KALITE. A light-green variety 

 of augite, found at the mouth of a river 

 whicli flows into lake Baikal In Siberia. 



BA'LA LIMESTONE. A dark-coloured 

 slaty limestone, forming a subordinate 

 portion of the Cambrian group of rocks. 

 In Westmoreland it is 100 feet in thick- 

 ness, and both there and in Wales con- 

 tains organic remains. 



BAL^'NID^ {<pd\atva, balcena,a. 

 whale). The Whale tribe of cetaceous 

 Vertebrata, in which the head constitutes 

 one-third, or even one- half, of the entire 

 length. By this disproportionate size 

 they are distinguished from the Delphi- 

 nidce, or Dolphin tribe. By the term 

 halcenoptcra {irrepov, a fin), De Lacepede 

 distinguished from the other balaenas 

 those whales which have an adipose fin 

 on their back, and are hence called fin- 

 ners by sailors. 



BALANCE {bilanx, from bis and lanx, 

 i. e. a duabus lancibus, a beam with 

 balances). One of the simple mechani- 

 cal powers, consisting of a lever turning 

 on a pivot or fulcrum, and constructed 

 for the purpose of finding the weight of 

 different bodies. The lever, or rod, of a 

 balance is termed the beam, and the parts 

 of the beam on each side of the pivot on 

 which it turns are its arms. In the com- 

 mon balance those arms are equal, and 

 balance each other; and its ends, to 

 which the body to be weighed and its 

 equivalent counterpoise are hung, are 

 called the points of suspension. 



1. Roman Balance, or Steel-yard. This 

 kind of lever differs from the common 

 balance, in having its supp;)it near one 



