370 ACROPHYSICS. 



pungent, orange colored fumes, from nitric acid, or aqua fortis ; 

 which consists of 14 by weight of nitrogen to 5 times 8 of oxygen ; 

 its formula being N + 5 O. Ammonia, or spirits of hartshorn, con- 

 tains 14 of nitrogen, to 3 of hydrogen ; expressed by N-f-3 H. 



Sulphur, is found chiefly in minerals, or volcanic effusions : and 

 by burning, it forms sulphurous acid gas, S -f 2 O, known by its 

 suffocating odor. Sulphuric acid, or oil of vitriol, contains 16 by 

 weight of sulphur, to 3 times 8 of oxygen, as expressed by the 

 formula S + 3 O ; or S. Selenium, is a rare element, resembling 

 sulphur. Carbon, is the chief constituent of all kinds of coal ; and, 

 in burning, it forms carbonic acid gas, C -f 2 O, which always exists 

 in the air as an impurity. Coal gas, consists of various carburets of 

 hydrogen. Boron, is a rare element, the basis of boracic acid, 

 B + 3 O ; found in borax. Silicon, is a dark brown solid, the basis 

 of sand ; which is silicic acid, S -f 3 O, and which may be rendered 

 soluble by heating it with potassa. Phosphorus, a soft, white inflam- 

 mable solid, abounds in the bones of animals, in the state of phos- 

 phoric acid, 2 P + 5 O, but combined with lime. Chlorine, is a 

 green gas, of a pungent odor, obtained from common salt ; and 

 which by uniting with hydrogen forms muriatic, or hydrochloric 

 acid, H + Cl ; while with oxygen it forms highly explosive gases. 

 Bromine, is a red liquid, found in sea water : Iodine, is a black 

 crystalline solid, found in the ashes of marine plants ; and Fluorine, 

 is a reddish brown gas, found in the mineral called fluorspar. All 

 these latter elements are electro-negative, like oxygen and sulphur ; 

 and they all form acids with hydrogen ; and, excepting fluorine, they 

 form acids also with oxygen. 



2. Under Metallic Chemistry, we include the study of the 

 metals, and their various compounds. The metals are characterized 

 by their peculiar lustre, and their being good conductors of heat and 

 electricity. They may be classed as the crypto-metals, or concealed 

 metals, which are the bases of the alkalies and earths ; and the 

 sapho-melals or common metals, several of which are found native, 

 that is, uncombined with any other elements. The metals are 

 generally obtained from their ores ; which are mostly oxides, sul- 

 phurets, or chlorides ; by heating them with charcoal or combustible 

 matter, which unites with the other elements, and sets the metal free. 

 Of the crypto-metals, Potassium, is as bright as lead, but much softer, 

 and so light that it floats on water ; burning at the same time, and 

 forming potassa, K -f- O, which is the caustic base of pearlash. 

 Sodium, is a whiter metal, the base of soda, N + O : and common salt 

 is the chloride of sodium. Lithium, is a very rare metal, the base 

 of the remaining alkali, lithia. Barium, and Strontium, are rare 

 metals, the bases of baryta and strontia : Calcium, is a white metal, 

 the base of lime, which is an oxide of calcium ; and Magnesium, 

 is the base of magnesia, the remaining alkaline earth. .Aluminium, 

 is the base of alumina, the chief constituent of clay : and Glucinium, 

 Yttrium, Thorium, and Zirconium, are rare metals, found in the 

 remaining earths, technically so called. 



Of the sapho-metals, or metals commonly found as such, seven 

 were known to the ancients ; to which the alchemists gave the names 



