BAY 



BEL 



salt be viewed as consisting of siilphat- I 

 oxide of sodium. 



BATH, CHEMICAL. An apparatus 

 for modifying and regulating tlie heat in 

 various chemical processes, by inter- 

 posing sand or some other substance 

 between the fire and the vessel intended 

 to be heated. The water bath, formerly 

 called balneum mar iae, and the sand bath, 

 are most commonly used. Solution baths, 

 consisting of saturated solutions, will 

 produce temperatures as high as 360°. 

 For higher temperatures, metal baths are 

 employed, as of mercury, fusible metal, 

 &c. ; the temperature may thus be raised 

 to 600°. 



BATH, ELECTRICAL. This is ad- 

 ministered by placing a person on an 

 insulating stool, and directing the elec- 

 tric current from the conductor to dif- 

 ferent parts of the body by means of some 

 pointed conductor. 



BATRA'CHIA (ySarpaxo?, a frog). An 

 order of the class Reptilia, comprising 

 the frog, toad, salamander, and siren. 



BATTERY, ELECTRICAL. An ar- 

 rangement of Leyden jars which commu- 

 nicate together by both their inner and 

 outer surfaces, and are thus rendered 

 capable of being charged with electricity 

 and discharged at the same time. 



1. Battery, Galvanic. A combination 

 of several pairs of zinc and copper plates 

 soldered together, and so arranged that 

 the same metal shall always be on the 

 same side of the compound plate. A 

 combination of this kind is sometimes 

 termed a compound hydro-electric battery, 

 or a voltaic pile or battery. 



2. Battery, Trough. In this apparatus 

 the zinc and copper plates are fastened 

 to a slip of mahogany wood, and united in 

 pairs by a piece of metal soldered to each. 

 The whole are then placed in a trough 

 of wood, or of Wedgewood's ware, divided 

 into cells, so that each pair of plates 

 shall enclose a partition of the trough, 

 each cell of the trough containing a plate 

 of zinc connected with the copper plate 

 of the succeeding cell, and a plate of 

 copper joined with the zinc plate of the 

 preceding cell. 



3. Constant Battery, A term applied to 

 a battery in which the effect of the cur- 

 rent is for a long time unimpaired, owing 

 to the employment of concentrated nitric 

 acid, by means of which the platinum, 

 and by analogy the carbon also, become 

 depolarized and relatively exalted in their 

 electromotive functions. Of this kind 

 are the batteries of Grove and Bunsen. 



50 



BAY. A projection of the ocean into 

 the continent, of less expanse than that 

 of a sea, but communicating with the 

 ocean by a broader passage. See Gulf. 



BAY SALT. A general name for 

 coarse-grained salt, but particularly ap- 

 plied to salt obtained by spontaneous 

 evaporation of sea-water in large shallow 

 pits or bays. 



BDE'LLIUM. A name applied to two 

 gum-resinous substances. One of these 

 is the Indian bdellium, or false myrrh, 

 procured from the Amyris commiphora. 

 The other is called African bdellium, 

 and is obtained from the Heudolotia 

 African a. 



BEAD-PROOF. A term denoting the 

 strength of spirituous liquors, as shown 

 by the continuance of the bubbles or 

 beads on the surface. 



BEARING. A term denoting, in 

 Navigation, the situation of one place 

 from another with respect to the points 

 of the compass. Thus, if A lies in the 

 direction of south-west from B, then to 

 an observer at B, A is said to bear south- 

 west, or to have a south-west bearing; 

 while to an observer at A, the point B 

 will bear north-east, or have a north-east 

 bearing. To take bearings, is to ascer- 

 tain the points of the compass on which 

 objects lie. 



BEATS. A term applied, in Music, 

 to the beatings or pulsations resulting 

 from the joint vibrations of two sounds 

 of the same strength and nearly the same 

 pitch ; that is, of two sounds differing 

 little, if at all, in intensity, and almost, 

 but not exactly, in unison : when the 

 unison is complete, no beats are heard. 



BEGUIN'S SULPHURATED SPI- 

 RIT. A variety of hydrosulphate of 

 ammonia, commonly called hepatized 

 ammonia. 



BE'LEMNITE {^eXenvov, a dart). An 

 extinct genus of the Cephalopods, allied 

 to the sepia, and having a long, straight, 

 and chambered conical shell, resembling 

 a dart, in the interior of the body. They 

 have been termed lapides lyncis, from 

 an old idea that they came from the lynx ; 

 and, from their resemblance to fingers, 

 petrified fingers, devil's fingers, spectre 

 candles, &c, 



BELLA'TRIX. A star of the second 

 magnitude, the smaller of the two bright 

 upper stars in Orion. It is marked -y by 

 Bayer, and 24 by Flamstead. 



BELL-METAL. An alloy of 100 parts 

 of copper with 20 to 25 of tin. 



BELL-METAL ORE. A designation 



