EXPLANATION OF SCIENTIFIC TERMS. 



AXIS OF REFRACTION. Seo Refrac- 

 tit-p Power. 



OF A MAGNET. See Magnetism. 



AZIMUTH. See Horizon. 



COM PASS. Seo Horizon. 



AZOTE, or AZOTIC GAS. (Greek a 

 privative, and xoe life,) so called because, 

 if inhaled alone it would be instantly de- 

 structive of life, is combined with oxygen 

 in the atmosphere, of which it constitutes 

 seventy-three parts in the hundred. This 

 gas is also called Nitrogen, because it is 

 believed to be the basis of Nitric acid or 

 *-/(jiia Fords. 



BALANCE See Gloss. I. 



BAROMETER. See Gloss. I. 



BASIL LEATHER, tanned sheepskin. 



BATTERY, ELECTRICAL, See Leyden 

 Final. 



, VOLTAIC. See Galvanic 



Circle. 



BERYL. See Emerald. 



BLACK-LEAD. See Carbon. 



BODY is any determinate portion of matter 

 which may act, or be acted upon, by other 

 bodies. 



BOILING. See Gloss. I. 



BOILING-POINT. See Gloss. I. 



BURNING-GLASS. See Gloss. I. 



CAIRNGORM. See Quartz. 



CALAMINE, an ore of zinc. 



CALCAREOUS SPAR. See Gloss. I. 



CALORIC, latent, specific, &c. See 

 Gloss. I. 



CALORIFIC RAYS. See Gloss. I. 



CALX. See Oxygen. 



CAOUTCHOUC, or INDIAN RUB- 

 BER, is an elastic resin or dried juice of 

 certain trees and plants, growing in South 

 America and the East Indies : the He- 

 vcea caoutchouc and latropha elastica of 

 the former; and the Urceola elastica of 

 the latter. In some parts of those coun- 

 tries boots and shoes are made of that 

 material. 



CAPACITY FOR HEAT. See Gloss. I. 



CAPILLARY TUBE. See Gloss. I. 



. ATTRACTION. See 



Gloss. I. 



CARBON is the chemical name for char- 

 coal, supposing it to be pure ; but pure 

 carbon is understood to exist only in the 

 diamond. Charcoal (the carbon of the 

 arts) is the coaly residuum of vegetable 

 substances which have been burnt in 

 close vessels, and is an oxide of carbon. 

 Carbon unites readily with oxygen, form- 

 ing a gas called Carbonic Acid. It is this 

 which is produced by the vinous fermen- 

 tation. The union of this acid with al- 

 kalies, and alkaline substances, or with 

 metals, forms what are called Carbonates : 

 thus we have Carbonate of Potash, Car- 

 Inmate of Lime, (Carbonate of Iron, &c. 

 Carbon enters into direct combination 

 with iron. Nine parts carbon to one of 

 iron is Carburet of Iron what has erro- 

 neously been called Plumbago or Black- 



lend. In the proportion of about a forty 

 fifth of the weight of the iron it forms 

 Cast-iron. Steel is a combination of about 

 one part of carbon to two hundred of 

 iron. This union of carbon and iron is 

 called Carbonization, and to decarbonize. 

 the cast-iron, or steel, is to drive off its 

 carbon, in the form of Carbonic A<-id (las. 

 Iron is said to be Case-hardened when its 

 outer surface is converted into steel. See 



CASE-HARDENING. See Carbon. 

 CAST-IRON, See Carbon. 

 CATOPTRICS, that part of the science of 



optics which treats of the reflexion of 



light. 



CENTIMETRE. See Metre. 

 CENTRE OF GRAVITY. See Gravity. 



- OF GYRATION. See Gyra- 



tion. 



- OF PERCUSSION. See Per- 

 cussion. 



-- OF PRESSURE. See Pressure. 



CENTRIFUGAL FORCE. See Gloss. I. 



CENTRIPETAL FORCE is that force 

 which draws a body towards a centre, 

 and thereby acts as a counterpoise to 

 the centrifugal force in circular motion. 

 Gravity is a centripetal force, preventing 

 the planets from flying off in a tangent, 

 as the stone does from the sling. 



CHARCOAL. See Carbon. 



CHEMICAL ATTRACTION, CHEMI- 

 CAL AFFINITY, AND ELECTIVE 

 ATTRACTION are different names for 

 that unaccounted-for action by which the 

 particles of one class of bodies, when pre- 

 sented to those of certain other classes, 

 conjoin to form new compounds, making, 

 apparently, a choice or election, of those 

 with which they unite. 



CHEMICAL COMBINATION is that 

 intimate union of two substances, whether 

 fluid or solid, which forms a compound , 

 differing in one or more of its essential 

 qualities from either of the constituent 

 bodies. 



CHORD OF AN ARC. See Angle. 



CHROMATICS (from the Greek chroma, 

 colour) is that division of the science of 

 optics which treats of the colours of light, 

 their several properties, and the laws by 

 which they are separated. 



CHROMATIC VERNIER. See Vernier. 



CIRCLE OF GYRATION. See Gyra- 

 tion. 



CIRCUMFERENCE. See Perimeter. 



COHESION. See Gloss. I. 



-- , ATTRACTION OF. See 

 Gloss. I. 



COLOUR .See Gloss. I. 



COLOURS, PRIMARY. See Gloss. I. 



COMBINATION OF BODIES. Sec 

 Chemical Combination. 



COMMENSURABILITY. See Ratio. 



COMPASS, AZIMUTH. See Horizon. 



-- , MARINER'S. See Mariner^ 

 Compass, 



