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LEFT CELSIUS SCALE 896 CENCI hoi, acetone and other compounds are produced. See also Nitro-cellulose. CELSIUS SCALE, another name for the Centigrade thermometric scale, from that of the inventor, Anders Celsius. See Thermometer. CELTS, the earliest Aryan settlers in Europe according to the common theory. They appear to have been driven west- ward by succeeding waves of Teutons, Slavonians, and others, but there are no means of fixing the periods at which any of these movements took place. Herodo- tus mentions them as mixing with the Iberians who dwelt round the river Ebro in Spain. At the beginning of the his- toric period they were the predominant race in Great Britain, Ireland, France, Belgium, Switzerland, northern Italy, Spain, and elsewhere. The Romans called them generally Galli, that is, Gauls or Gael. They appear to have reached the zenith of their power in the 2d and 3d centuries B. C. Some tribes of them, overrunning Greece, settled in a part of Asia Minor, to which the name of Galatia was given. They finally went down before the resistless power of Rome, and either became absorbed with the conquering races or were cooped up in the extreme N. W. of Europe. At an early date the Celts divided into two great branches, speaking dialects widely differing from each other, but doubtless belonging to the same stock. One of these branches is the Gadhelic or Gaelic, represented by the Highlanders of Scot- land, the Celtic Irish, and the Manx; the other is the Cymric, represented by the Welsh, the inhabitants of Cornwall, and those of Brittany. The Cornish dialect is now extinct. _ The sun seems to have been the prin- cipal object of worship among the Celts, and groves of oak and the remarkable circles of stone commonly called "Druid- ical Circles," their temples of worship. All the old Celts seem to have possessed a kind of literary order called Bards. The ancient Irish wrote in a rude al- phabet called the Ogham; later they employed the Roman alphabet, or the Anglo-Saxon form of it. The chief litera- ture existing consists of the hymns, mar- tyrologies, annals, and laws of Ireland, written from the 9th to the 16th cen- turies. The Scottish Gaelic literature extant includes a collection of manu- scripts in the Advocates' Library, Edin- burgh, some of which date from the 12th century; the "Book of the Dean of Lis- more," 16th century; a number of songs from the 17th century to the present day; and the so-called poems of Ossian. The Welsh literary remains date from the 9th century, and consist of glossa- ries, grammars, annals, genealogies, his- tories, poems, prose tales, etc. CEMENT, a substance with which two bodies are joined together. There are many varieties, according to the special needs of different trades. In building the principal are known as Portland and Roman. There are many places in the United States in which are found the ingredients necessary for the manufac- ture of the various cements described below, and many different varieties of the article are made. Where Portland cement is specified in a building contract the imported variety is meant. Portland Cement was patented in Eng- land by Joseph Aspdin in 1824. It is so called because it resembles in color Port- land-stone. It is manufactured by cal- cining a mixture of clayed mud from the Thames with a proper portion of chalk. The calcined mass is then reduced to a fine powder, and intimately mixed with the addition of water. The resulting paste is molded into bricks, dried and burnt. The heat during the process of calcining must be a white heat, other- wise the carbonic acid and water may be expelled without the reaction between the lime and the clay necessary for the production of cement. The material is then assorted, all which has been too much or too little calcined being set aside and pulverized. Roman Cement is a name given to cer- tain hydraulic mortars, varying consid- erably in their chemical composition, though physically possessing the same general character. Limestone is cal- cined and mixed with sand in various proportions. Any limestone containing from 15 to 20 per cent, of clay will, when properly prepared, form this cement. Calcine any ordinary clay and mix it with two-thirds its quantity of lime, grind to powder, and calcine again. The epithet Roman is improperly given, since the preparation was entirely unknown to the Romans. Hydraulic Cement is a kind of mortar used in building piers and walls under or exposed to water. There are many varieties, one of the best being composed of ground Portland-stone, 62 parts; sand, 35, and litharge, 3. The production of cement in the United States in 1919 was: Portland, 80,287,000 barrels, valued at $135,- 685,000; natural Cement, 528,000 bar- rels, valued at $597,000. Pennsylvania ranks first in the production of Port- land Cement, with 25,222,000 barrels in 1919. CENCI, BEATRICE (chen'che), called the beautiful parricide, the daughter of(