EXPLANATION OF SCIENTIFIC TERMS. 



CALORIC, LATENT, is that portion of the 

 fluid matter of heat which exists in any 

 body without producing any effect upon 

 another ; what produces an effect being 

 termed free or sensible Caloric. 



' SPECIFIC. Although all bodies 



possess some quantity of Caloric which is 

 latent, yet the quantity in each varies 

 with the nature of the body. The rela- 

 tive proportion that any body retains 

 without the effects being sensible, is 

 termed the Specific Caloric of that body; 

 and its power of retention is called its 

 Capacity for Caloric. 



CALORIFIC RAYS are those rays or 



emissions from the sun, or any burning 



body, which impart the sensation and 



other effects of heat. 



CAPACITY FOR HEAT. See Caloric, 



Specific. 



CAPILLARY TUBE. A hair (Latin ca- 

 pillus) is a tube ; and hence tubes, which 

 are so small as to be likened to hairs, are 

 termed Capillary Tubes. 



ATTRACTION. If an 



open capillary tube be placed upright, 

 with its lower end immersed in a vessel 

 of water, the liquid will rise in the tube, 

 to a greater height than the surface of 

 that which surrounds it. This is not in 

 conformity with the commonly observed 

 laws of the ascent of fluids ; and, there- 

 fore, the cause of the phenomenon is de- 

 nominated Capillary Attraction. 

 CATOPTRICS, that part of the science of 

 optics which treats of the Reflexion of 

 Light. 

 CENTIGRADE THERMOMETER. 



See Thermometer. 



CENTRE OF GRAVITY. See Gravity. 

 OF GYRATION.- See Gyra- 

 tion. . 



OF PERCUSSION. See Per- 



cussion. 



OF PRESSURE. See Pressure. 



CENTRIFUGAL FORCE is that by 



which the parts of a body moving round 



a centre endeavour to recede from that 



centre. Thus, if a stone be tied to one 



end of a string, and swung round in a 



circle while the other end of the string is 



held by the hand, as the centre of motion, 



the stone will be felt pulling the hand as 



if endeavouring to escape ; and, in fact, 



if allowed, would fly off in a tangent to 



the circle in which it moves. It is thus 



that a stone is projected from a sling. 



CHEMICAL COMBINATION is that 



intimate union of two substances, whe- 



her fluid or solid, which forms a com- 



>ound differing in one or more of its 



;sse*ntial qualities from either of the con- 



itituent bodies. 



IORD OF AN ARC. See Angle. 

 IROMATICS (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. 



CIRCUMFER EN CE. See Perimeter. 



COHESION (Latin coharere, to stick to- 

 gether) is that relation among the com- 

 ponent particles of a body, by which they 

 are found to cling together, requiring 

 more or less effort to force them asunder. 



ATTRACTION OF, is a 



name given to the unknown principle 

 Avhich makes the particles of a body cohere, 

 or stick together. 



COLOUR is a general name for those mo- 

 difications of Light (whether direct or 

 reflected from other bodies) by which it 

 is distinguished into species that affect 

 the eye with separate sensations. The 

 colour of a body is designated by the spe- 

 cies of light which is reflected from its 

 surface. 



COLOURS, ACCIDENTAL. See Acci- 

 dental Colours. 



PRIMARY. These are red, 



orange, yellow, green, blue, indigo, and 

 violet, being the seven different colours 

 into which a solar ray of light, which is 

 white, may be decomposed or separated. 

 White is, therefore, a compound of those 

 seven, and black is the absence of all 

 colours. See Prismatic Spectrum. 



COMBINATION OF BODIES. See 

 Chemical Combination. 



COMMENSURABLE. See Ratio. 



COMPOSITION OF FORCES. See 

 Forces, Composition of. 



COMPRESSIBILITY is that quality of a 

 substance, whether solid or fluid, which 

 allows it to be pressed, or rather squeezed, 

 into a less bulk than it naturally occu- 

 pies. The ultimate particles of all bodies 

 are supposed to be incompressible. See 

 Hardness. 



CONCAVE MIRRORS. See Mirror. 



LENSES. See Lens. 



CONDENSATION is causing a mass of 

 matter to occupy less space by means of 

 the closer approach of its particles. When 

 this is done by outward force, it is com- 

 pression. The term is commonly used 

 with regard to air, gas, and vapours. 

 The two former are condensed, and their 

 elasticity increased by compression ; and 

 the latter are condensed into liquids and 

 solids by cold 



CONDUCTORS OF CALORIC, OR OF 

 HEAT, are bodies which, when heated 

 in one part, comimmicate the effects to 

 the other parts. This is the case with 

 most natural bodies, but some have that 

 power in a much greater degree than 

 others : thus a rod of dry wood may be 

 burned at one end, while the other end 

 shall he little affected. 

 CONE. A cone is a solid with a circular 



