CALCEOLARIA 



1048 



CALCIUM CARBIDE 



Calais has an interesting history, dating back 

 to the medieval period of England and France. 

 Old Calais was a celebrated fortress. It was 

 defended by a citadel built in 1560 and by 

 four old forts. A new circle of defenses, 

 strengthened by a deep moat, now surrounds 

 the town and its suburb of Saint Pierre, 

 which are hemmed in by the canal and harbor. 

 Some of the old buildings, including a Gothic 

 cathedral and the town hall, still remain. 



In 1346, after the Battle of Crecy, Edward 

 III besieged Calais for nearly a year, when 

 famine forced the town to surrender. Through 

 the entreaty of Queen Philippa, the inhabitants 

 wqre spared, but were later expelled to make 

 room for English settlers. For two centuries 

 Calais was ruled and largely populated by the 

 English. In 1558, England's war with France 

 ended in the loss of Calais to Francis, Duke 

 of Guise. This was the last of the English 

 possessions on the Continent, and its loss had 

 important effects upon English history (see 

 ENGLAND, subhead History). In 1595 it was 

 captured by Spain but was restored to France 

 in 1598 by the Treaty of Vervins. The town 

 has important manufactures of silk and cotton 

 goods and bobbinet lace. 



An international tunnel to connect Calais 

 with the English coast has long been considered, 

 and work was actually begun on this project 

 at one time. However, political leaders of 

 both France and England decided that in the 

 event of war between the two nations such a 

 tunnel would be a menace to both, and the 

 work was abandoned. In the War of the Na- 

 tions (began 1914) the Germans twice tried to 

 take this important seaport, because it would 

 open the way to an invasion of England, but 

 they were unsuccessful. The great German 

 offensive of March, 1918, had this important 

 port as one of its objectives. 



CALCIMINE, kal'simine, or cold water 

 paint, has for its basis whiting or carbonate 

 of lime. Calcimine must not be confused with 

 whitewash, which is made from caustic lime. 

 Carbonate of lime, or whiting, will not adhere 

 to a surface; therefore it is necessary to use a 

 binder, which is usually glue, casein or one of 

 the resinous gums. Calcimine is extensively 

 used for inside decorating because of its beauty, 

 cheapness and hygienic qualities. 



The United States Department of Agricul- 

 ture gives the following directions for making 

 calcimine : 



Take 16 pounds of dry Paris white (whiting), 

 and pulverize till free of lumps, then mix with 



one gallon of boiling water. To this add one- 

 half pound of white sizing glue after it has 

 soaked for four hours in one-eighth gallon of 

 cold water. The glue should be dissolved in a 

 glue pot. Any tint desired may be given the 

 calcimine by stirring liquid coloring into the 

 stock. The above recipe will make about two 

 gallons of calcimine weighing 12% pounds per 

 gallon. It may be used at once, but is better 

 after standing for half an hour. Ocher, cochi- 

 neal and logwood are the materials usually used 

 for tinting. 



The word is sometimes incorrectly written 

 kalsomine. 



CALCITE, kal'site, a term applied to various 

 minerals, all of which are modifications of 

 crystallized carbonate of calcium. Calcite in- 

 cludes limestone, all the white and most of 

 the colored marbles, chalk and Iceland spar. 

 It is generally white, although shades of gray, 

 yellow, violet, green, red and blue are known. 

 Calcite is found in commercial quantities in 

 Rossie, N. Y., in Copper Mine in the Lake 

 Superior region, in Warsaw, 111., and also in 

 England and in Androsburg, South Africa. 

 Smaller quantities occur also in other widely- 

 scattered communities. 



CALCIUM, kal'seum, is never found in a 

 free state, but in its compounds is one of the 

 most, abundant and most widely distributed of 

 the chemical elements, forming about 3.5 per 

 cent of the earth's crust. It is a metal whose 

 oxide is quicklime; its hydroxide is slaked 

 lime. Its phosphate forms the main part of 

 the mineral matter of the bones of animals. 

 As a carbonate it appears in calcite, chalk, 

 limestone, marble, coral and shells, and as a 

 sulphate it forms large deposits known as gyp- 

 sum, alabaster and selenite. Besides, it appears 

 as a constituent in many minerals, such as 

 fluorspar and apatite, and is found in all soils, 

 in the ash of plants, dissolved in sea water and 

 in all springs. The hardness of spring water 

 is almost always due to the calcium compounds 

 dissolved in the water.' When quite pure it 

 is a silver-white metal with a high luster, 

 soft enough to be cut with a file, though much 

 harder than lead. It is about one and a half 

 times as heavy as water, and is ductile and 

 malleable. See each mineral named; also 

 DUCTILITY; MALLEABILITY. J.F.S. 



CAL'CIUM CAR 'BIDE, a hard, brittle, dark 

 gray, crystalline solid. It has a lustrous sur- 

 face when freshly broken, but quickly tarnishes 

 in the air. The method of making it cheaply 

 was discovered a'bout 1895 by T. L. Willson, a 

 Canadian engineer. It is made on a large scale 

 by heating a mixture of lime and coke in an 



