Page:The New International Encyclopædia 1st ed. v. 04.djvu/474

* CELLULOSE. 404 CELT. pends largely on the LMiieeiitiation of the acid. Moderately dilute sulphuric acid transforms it, iu the cold, into 'colloidal cellulose,' which is soluble iu water, but is rcprecipitated on addi- tion of a trace of acid or of salt solution. If cellulose is dissolved in stron;,' sulphuric acid and the solution is diluted with water, a jjelat- inous mass separates out, which is known as amyloid. In the presence of acid, amyloid is, like starch, colored blue by a solution ot iodine. This transformation may be employed for de- tecting the presence of cellulose. Vegetable parchment, too, is made from cellulose by the use of sulphuric acid; for this purpose unsized paper is iuuuersed for a few instants into concentrated sulphuric acid and then ininiedialely washed with water, the paper thus becoming more dura- ble and less permeable to liquids. Another trans- formation of cellulose, elTected by sulphuric acid, may be mentioned here: if cellulose derived from cotton is digested for some time with strong sulphuric acid, then diluted with water and sub- jected to prolonged boiling, the cellulose is partly converted into grape-sugar. With strong nitric acid cellulose forms ex- plosive nitrates known as nitro-celluloses, the composition of which dcjH'nds on the strength of the acid employed and the duration of the re- action. Collodion is a .solution mainly of the tetra-nitrate and the penta-nilrate of cellulose in a mixture of alcohol and ether, fruncotton is the hexanitrate of cellulose, obtained by the prolonged action of a mixture of concentrated nitric and sulphuric acids. If distilled in retorts, out of contact with air, •cellulose is decomposed with formation of methyl alcohol, formic acid, acetic acid, and various hydrocarbons. All of these products are formed also in the destructive distillation of wood. Cellulose is employed, in one or the other form, for a variety of purposes in the arts. It is largely us'ed in the manufacture of paper and of explosives. By dissolving the nitrocelluloses of collodion in melted campluir the sulistance known as celluloid is obtained, and celluloid is now ex- tensively employed for making various articles in common use. Practical use is now also made of the swelling capacity of cellulose. The fact that the substance, when wet, will rapidly fill up a hole that has been made through it, has sug- gested the idea of employing it to prevent leak- age through shot-holes. Within recent years the usefulness of cellulose for this purpose has been repeatedly demonstrated, and at present the substance is actually employed as a packing for the sides of war-vessels. See Cell; Cabbohy- DRATKS. CELMAN, sal'nian. Miguel Juarez. See JVAHKZ (KLMAN, MiGlEL. CELSIUS, sel'si-us or sel'shl-iis, Anders (1701-44). A Swedish astronomer, born in Up- sala. In 17.30 he became professor of astronomy in Upsala Universitj-. He undertook a journey to prominent observatories of Europe in 1732, and in 1740 built the observatory at Upsala, and was appointed its director. In 1737 he took part in the Krcnch expedition sent to measure one degree of meridian in the polar regions. He was one of the first to call attention to the sub- sidence of the sea-level off the northern coast of Sweden, and urged the introduction of the Gregorian calendar, to supersede the .lulian. In his monograph On the ilensurement of Heat (1742), he presented the lirst idea of the centi- grade, also known as the Celsius, thermometer. He published, among other scientihc treati.ses, De Obscnntionihiis pro I'igura Telluris Deter- minnndii in (lullia llabitis. CELSIUS, Olof von (1716-94). A Swedish historian. He was born in I'psala, Avhere he l>i'came professor of history in 1747. lie was appointed Bishop of Lund in 1777. In 1742 he founded the first literary journal in Sweden. His works on (iuslavus I. and Kric XIV. are characterized by careful investigiition and strict truthfulness. He died while engaged upon his celebrated work, ,Srea rilccs kt/rkohistoria. which is the first attempt at a compilation of Swedish Church history. CEL'SUS (Cik. Kf?.aoc, Kelsos). A Greek philosopher of the .Second Century, the earliest literary ojjponent of Christianity. He wrote, in 177 or 178. an attack on Christianity, called A6;of ' A'A7]Hij(j or A True Discourse. This work has been lost, but by means of Origen's reply, the Contra Celsum, it has been ingeniously recon- structed by Keini {Celsus' walires Wort wieder- heri/rslrlll, 1873). See Okige.x. CELSUS. One of the adventurers, fancifully styled by Trebellius Pollio the 'Thirty Tyrants,' wiio, between A.u. 200 and 207, rose to usurp the imperial throne of Home. A military trib- inie, resident in Africa, he was proclaimed Em- peror by Vibius Passienus, jiroconsul of the province, and others; but on the seventh day of his ill-starred reign he was murdered in Sicca. CELSUS, AuT.us Cornelius. A Latin physi- cian and writer, who nourished proliably in the reign of Tiberius. He was called the Koman Hippocrates, because he generally followed the great "father of medicine,' and introduced the Hippocratic system among the Romans. Celsus wrote not only on medicine, but also on rhetoric, history, pliilosophy, the art of war, and agricul- ture. His style is succinct and clear, but full of Graecisms. Only jiart of his encyclo]iadic work survives, the Ue .Mcdicina, which is divided into eight books. The portions relating to surgery are exceedingly interesting and valuable, because Celsus has there given an account of the opinions and observations of the Alexandrian school of medicine. The first edition of the De .Medirinn appeared in Florence in 1478. The standard edition is that of Darcml)erg (Leipzig. 18591. The De Medicina has lieen translated into Eng- lish by J. Grieve (3d ed., Edinburgli, 1837). CELT. An implement used among the primi- tive peoples of every jiart of tlic world. The term is from the Welsh etlll, which signifies a flint, or ilintstonc — a ty|)ical form of the imple- ment. In developed form it is a chisel or grooveless a.e of any hard stone, used either with or without a haft, in the former case hafted either in line with or transverse to its length and edge. In its nascent form it is an elongated pebble or other stone of convenient size, used in the hand with centrii)etal (i.e. in- ward and downward) strokes. Next to the hammerstone it is the most primitive implement used l>y man (if not by the quadrumana): in- deed, the hammer and celt, with the muller. pestle, and haftless axe a little higher in the scale, are all dili'erentiated from the original protolith. or designless pebble, and are closely akin in both form and function. .t first shaped