SCIENTIFIC TERMS. 139 



Baiium, a recently discovered metal, the base of Barytes. 



Barometer, an instrument for ascertaining the weight of the atmos- 

 phere. See page 40. 



Barytes, an earth usually found in combination with an acid, as the 

 Sulphate and Carbonate of Barytes. It received its name from its 

 weight, being the heaviest of all the earths. It is a violent poison. 



Basaltes, a kind of stone of a very ponderous nature found in large 

 masses. The Giant's Causeway in Ireland is a range of basaltic 

 columns. 



Base, a chemical term applied to denote the earth, the alkali or the 

 metal which is combined with an acid to form a salt. 



Battery, " Electrical and Galvanic." See pages 62 and 65. 



Belemnite, a kind of fossil, vulgarly called a thunderbolt. 



Beryl, a gem of a pale yellow, green, or blue colour, sometimes called 

 Aquamarine. 



Bismuth, a metal of a white reddish colour, rather hard, but neither 

 malleable nor ductile. A preparation of it is occasionally used in 

 cosmetics. 



Blende, an ore of zinc. 



Boiling, Theory explained, page 44. 



Bolognian Stone, a stone of a phosphoric nature, first discovered near 

 Bologna in Italy. 



Boracic-acitl, a recently discovered substance formed from borax. 

 When burnt with alcohol, it communicates a green colour to the 

 flame. 



Brass, & well known artificial metal made of zinc and copper. 



Bronze, a compound of copper, tin, and sometimes zinc. This com- 

 pound is specifically heavier than either of the metals separately. 

 From its not being so liable to become oxidized as pure copper, it 

 is used for statues, cannon, and other works exposed to the air. 



Calamine, an ore of zinc used in making brass. 



Calcareous, a term applied to earths or combinations of lime with 

 carbonic acid gas, as chalk, which is a carbonate of lime, marble, &c. 



Calcium, the metallic base, of lime. 



Caloric, the supposed matter of heat or atomic motion. See page 15. 



Calorimeter, an instrument for ascertaining the quantity of heat disen- 

 gaged from any body during combustion. 



Calx, a metal combined with oxygen through combustion. 



Camera Lucida, a contrivance to make the image of any thing to 

 appear in a darkened room. 



Camera Obscura, an optical machine by which the images of external 

 objects are received through a double convex glass, and exhibited on 

 a white ground placed within the machine. 



Caoutchouc, Indian-rubber, a gum exuding from various trees and 

 plants in South America. 



Capillary, a term applied to a species of " Attraction." See page 14. 



Carbon, the base of wood, coal, &c. See page 15. 



Carbonates, Salts formed by the combination of carbonic acid gas 

 with any base. 



Carbonic Acid Gas, the heaviest of the gases. See page 73. 



Carbuncle, a stone of the ruby kind, of a blood-red colour. 



