308 



THE CENTURY BOOK OF FACTS. 



Glauber's-Salt, 



Glucose, 



Iron Pyrites, 



Jeweler's Putty, 



King's Yellow, 



Laughing Gas, 



Lime, 



Lunar Caustic, 



Muriate of Lime, 



Niter or Saltpeter, 



Oil of Vitriol, 



Potash, 



Realgar, 



Red Lead, 



Rust of Iron, 



Sal-ammoniac, 



Slacked Lime, 



Soda, 



Spirits of Hartshorn, 



Spirit of Salt, 



Stucco, or Plaster of Paris, 



Sugar of Lead, 



Verdigris, 



Vermilion, 



Vinegar, 



Volatile Alkali, 



Water, 



White Precipitate, 



White Vitriol, 



Sulphate of Sodium. 

 Grape Sugar. 

 Bi-Sulphide Iron. 

 Oxide of Tin. 

 Sulphide of Arsenic. 

 Protoxide of Nitrogen. 

 Oxide of Calcium. 

 Nitrate of Silver. 

 Chloride of Calcium. 

 Nitrate of Potash. 

 Sulphuric Acid. 

 Oxide of Potassium. 

 Sulphide of Arsenic. 

 Oxide of Lead. 

 Oxide of Iron. 

 Muriate of Ammonia. 

 Hydrate Calcium. 

 Oxide of Sodium. 

 Ammonia. 

 Hydro-Chloric, or Muriatic 



Acid. 



Sulphate of Lime. 

 Acetate of Lead. 

 Basic Acetate of Copper. 

 Sulphide of Mercury. 

 Acetic Acid (diluted). 

 Ammonia. 

 Oxide of Hydrogen. 

 Ammoniated Mercury. 

 Sulphate of Zinc. 



Chemistry was introduced into Spain by 

 the Moors about 1150. The Egyptians and 

 Chinese claim an earlier acquaintance with 

 chemistry. The first chemists were alchemists ; 

 but chemistry was not a science until the seven- 

 teenth century, during which it was promoted 

 by Bacon, llooke, Mayow, and Boyle. In the 

 early part of the eighteenth century, Dr. 

 Stephen Hales laid the foundation of pneumatic 

 chemistry, and his contemporary, Boerhaave, 

 combined the study of chemistry with medicine. 

 These were succeeded by Bergman, Stahl, 

 Black, and others. In 1772, Priestley pub- 

 lished his researches on air, having discovered 

 the gases, oxygen, ammonia, etc., and thus 

 commenced a new chemical era. The nine- 

 teenth century opened with the brilliant dis- 

 coveries of Davy, Dalton, Faraday, Thompson, 

 and Silliman. Organic chemistry has been very 

 greatly advanced by Berzelius, Liebig, Dumas, 

 Laurent, Hoffmann, Cahours, Frankland, and 

 others, since 1830. 



Climate. Climate is the state of the at- 

 mosphere in regard to temperature, winds, 

 moisture, and salubrity. 



The climate of a place as regards tempera- 

 ture depends upon : 



Latitude. The general law is that the 

 amount of heat is greatest at the equator, and 

 diminishes toward the poles. There are three 

 reasons for this: 1. The sun's rays fall per- 

 pendicularly upon the earth at the equator, 

 and more and more obliquely as we go toward 

 the poles. 2. The area covered by a given 

 amount of heating power from the sun is 

 smaller at the equator. 3. Where the sun's 

 rays fall perpendicularly they pass through a 

 less amount of atmosphere, and the absorption 

 of heat is less. 



Altitude The decrease in temperature is 

 about 3 deg. F. for every 1,000 feet of eleva- 

 tion. As the air receives most of its heat by 

 radiation and reflection from the earth, and as 

 the higher we go the less dense the air, the less 

 heat is absorbed either from the earth or from 

 the direct rays of the sun . 



Prevailing Winds. Winds blowing from the 

 tropical regions carry the heat with them, and, 

 conversely, winds from the polar regions lower 

 the temperature. Whichever wind prevails 

 throughout the year in a given place will con- 

 sequently modify the temperature of that place. 



Length of Day. During the day the earth 

 receives from the sun more heat than it radiates 

 into space ; while during the night it radiates 

 more than it receives. Hence a succession of 

 long days and short nights results in an accu- 

 mulation of heat, raising the average temper- 

 ature and producing summer ; while long 

 nights and short days result in a temperature 

 below the average, producing winter. The 

 heating power of the sun is greater in summer, 

 because at that season it is shining more di- 

 rectly upon that part of the earth, and con- 

 versely in winter. Tn the tropical regions the 

 inequality of day and night is very little, but 

 increases toward the poles. The temperature 

 in the tropics is therefore more uniform. The 

 length of day makes up for the lessened inten- 

 sity of the sun's rays; hence a place in high 

 latitude may have at times higher tempera- 

 ture than a place within the tropics. 



Ocean Currents. The warm waters of tho 

 tropical regions being brought toward the 

 polar regions bring the heat with them, radia- 

 ting it into space, and it is absorbed by the 

 atmosphere. 



Mountain Ranges. A mountain range will 

 make a country near it warmer or colder, ac- 

 cording as it shields it from a cold or warm 

 wind. 



The Distribution of Laml <in<l Water. Land 

 heats or cools rapidly, absorbing or emitting 

 but little heat. Water heats or cools slowly, 

 absorbing or emitting large quantities of heat. 

 Hence the land is subject to great and sudden 

 changes of temperature ; the water to small and 

 gradual changes. Places situated near the sea 

 have, therefore, a more equable climate. 



Character of Soil. Dry, sandy soil heats 

 and cools more rapidly than wet and marshy 

 lands ; hence the latter will have a more uni- 

 form temperature. 



Slope of Land. Land which slopes so that 

 the sun's rays will strike it nearer vertically 

 will receive more heat. The south side of a 

 hill is warmer in winter than the north side. 



In regard to winds the climate of a place 

 depends upon : 



