138 VOCABULARY OF 



Antimony, a brittle metal of a white colour. It is used in combi- 

 nation with other metals for printers' types, and for specula for 

 telescopes. 

 Apparatus, a term applied to the different parts of machinery used in 



philosophical experiments, chemical utensils, &c. 

 Aquafortis, another term for " Nitric Acid." 



Aqua-regia, or " Nitro -muriatic acid," a mixture of nitric and mu- 

 riatic acid, in the proportion of tivo parts of the former to one of 

 the latter : this alone will dissolve gold. 



Arbor Diana, or Silver-tree, Diana being the symbolical name given 

 by ancient alchymists to silver. Form a solution of silver by dis- 

 solving a piece of silver, as a sixpence, in nitric acid. Dilute this 

 very considerably, and pour it into a small decanter or phial with a 

 flat bottom. Into this pour an ounce or two or more of mercury ; 

 the silver will in the course of a few days, if kept quiet, become 

 precipitated on the mercury, and form a beautiful arborescence. 

 Arbor Plumbi, or Lead-tree. This is an arborescence of lead somewhat 

 similar to the above, and is thus made. Fasten a piece of zinc to 

 one end of a spiral-shaped wire, and let the other end of the wire 

 be thrust through a cork. Form a solution of sugar of lead in 

 spring water and filter it ; fill a phial or decanter with the solution, 

 and immerse into it the zinc ; in a few days the lead will be preci- 

 pitated on the zinc, and arboresce in a very beautiful manner. 

 Areometry, the science of measuring the density and gravity of fluids. 

 Arsenic, a metal usually found in combination with sulphur ; when 

 reduced to a metallic state it is of a brilliant colour, and at the same 

 time the most brittle and the softest of metals. It is extremely 

 poisonous. 



Asbestus, a mineral celebrated for its resisting fire. It is of a fibrous 



nature, and has been spun into cloth. This cloth when soiled may 



be restored to its primitive whiteness by being thrown into a clear 



fire. 



Asphaltum, a kind of bitumen or pitchy substance, found in various 



parts of the earth. 



Atmometer, an instrument contrived for measuring the quantity of ex- 

 halation in a given time. 



Atmosphere, that invisible fluid that surrounds our earth. It received 

 its name from the Greeks, in consequence of the vapours which are 

 continually mixing with it. See page 35. 

 Atomic Motion, a supposed rapid motion of the atoms of bodies which 



produces heat. 

 Attraction, a term used to imply that power by which all bodies have a 



mutual tendency towards each other. See page 1 1 . 

 Aurora Borealis, a meteor sometimes seen in the northern part of the 



heavens. See page 57. 



Aurum Fulminans, a dangerous fulminating powder made of gold. 

 Azote, the atmospheric air deprived of its oxygen. It was first disco- 

 vered in 1772, by Dr. Rutherford, of Edinburgh, and its properties 

 ascertained by Priestly and Cavendish. See page 73. 

 Balloon, a term applied to a chemical receiver of a spherical shape, 

 also to a well known body used for aerostation. 



