THE 



712 



THb 



pensation for ihe same : bete, compen- 

 ation. 



THKI'NA., \A. saline base, consisting of 



THEI'NE. ) snow-white acicular crys- 

 tals, of a beautiful silky lustre, extracted 

 from tea. It appears, however, to be 

 identical, in its composition and charac- 

 ters, with caffeine. 



THE'ISM from S-o;, God. The belief or 

 acknowledgment of the existence of a 

 Supreme Being ; opposed to atheism, and 

 differing from' rfmm, which, though it 

 acknowledges the existence of a God, de- 

 nies revelation, which theism does not. 



THE'NA.RD'S BLUE. Cobalt Blue. A 

 blue pigment, of which arseniate or phos- 

 phate of cobalt and alumina are the 

 bases. 



THEOBRO'M\. A genus of shrubs. Poly- 

 adelphia Decandria. Name from 8-of, 

 a god, and /SgciifAa., food, on account of the 

 deliciousness of its fruit. The Chocolate- 

 nut-tree, or tree which affords the Cocoa- 

 nut, is the best known species. South 

 America. 



THEOC'RACY, &-os, God, and x^arta, 

 I rule. The government of a state imme- 

 diately by God. 



THEOC'RASY, 9iof, God, and X^OHTK;, 

 mixture, anciently signified the inti- 

 mate union of the soul with God in con- 

 templation. 



THEOD'OLITE. An instrument used in 

 surveying, for mousurir.g angles. It is 

 mostly used in determining particular 

 stations, and in running base lines, being 

 the most perfect of all the angular in- 

 struments. 



THEOG'ONY, Qioyoma The generation 

 of the Gods. That branch of heathen 

 theology which taught the genealogy of 

 the deities. 



THEOL'OGY, from 05. God, and /eye?, 

 doctrine. Divinity : the science which 

 treats of the existence, character, and at- 

 tributes of God, his laws and govern- 

 ment, the doctrines we are to believe, 

 and the duties we are to practise. It con- 

 sists of two parts, natural and revealed. 



THEOR'BO, Ital. tiorba. A musical in- 

 strument, like a large lute, except that it 

 has two necks, the second and longer of 

 which sustains the four last rows of 

 chords, which are to give the deepest 

 sounds. The theorbo has 8 bass or thick 

 strings, twice as long as those of the lute, 

 which excess of length renders the sound 

 exceedingly soft and long continued. 



THE'OREM, Sica^fjut, from Bia^iiu, to 

 see. A demonstrative proposition: a pro- 

 position in which some property is as- 

 serted, and the truth of it required to be 

 proved. It differs from a problem, which 

 requires something to be doae. 



THE'OBT, 8w(i, from btt^ui, to see. 



A collected view of all that is known on 

 any speculative subject. A theory is pro- 

 perly a collection or set of theories, es- 

 tablished on independent evidence : an 

 hypothesis is a proposition assumed to ac- 

 count for certain phenomena, and has no 

 other evidence of its truth than that it 

 affords a satisfactory explanation of those 

 phenomena. These terms are very fre- 

 quently confounded, both in speaking and 

 writing, but should be kept perfectly dis- 

 tinct, as they are both required in thtse 

 speculative days. 



THEO'SOPHISTS, &9f and g-ofiat, wisdom. 

 Those who pretend to derive their know- 

 ledge of God from direct inspiration. 



THERAPEU'TICS, 6icc.viuTtr,, from 8t- 

 gTlua, to cure. A branch of pathological 

 science, which considers the application 

 of the remedies and means employed, 

 with a vie w to prevent and to cure diseases. 

 THER'MAT., from therma,a. warm spring : 

 Oie/uAf , warm. A term chiefly applied to 

 warm springs, as the Geysers. 

 ' THER'MO-ELECTRIC'ITY. E'ctricity de- 

 veloped by heat (0itt-/)). 



THERMOM'ETER, from Stj.cMj, heat, and 

 /*Tfo, a measure. An instrument for 

 measuring the variations of the sensible 

 heat of bodies. It consists essentially of 

 a hollow glass tube, hermeti- 

 cally sealed, and blown at one 

 end in the shape of a small 

 globe. This bulb part of the 

 tube is filled with mercury, 

 which it the only fluid that 

 expands equally at all tem- 

 peratures between 39 and 

 600. When, for instance, the 

 bulb is immersed in boiling 

 water, the mercury expands, 

 and rises in the tube to a 

 height which, in the common 

 thermometer, is denoted by 

 212; when again it is im- 

 mersed among pounded ice, 

 the mercury contracts, and falls in the 

 tube to a point in like manner marked 

 32. The space between these points is 

 divided into 180 equal degrees, and these 

 points, with any others that may be 

 wanted, being marked upon a scale 

 (usually ivory), and the glass tube being 

 attached to it, a Fahrenheit's thermometer 

 is made. In England, Fahrenheit's ther- 

 mometer is commonly used, but on the 

 Continent, particularly in France, the 

 Centigrade thermometer is almost exclu- 

 eively used. In this instrument, the in- 

 terval between the freezing and boiling 

 points of water is divided into 100, so 

 that a degree on the scale of Fahrenheit's 

 thermometer is equal to 5-9ths of a de- 

 gree on that of the Centigrade. Rfau- 

 mur't thermometer i* in use in Germany 



