SEM 



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SEN 



SRM'IXAL LEAVES. The leaves of a 

 plant which first sprout forth from the 

 sown seeds. 



SEMI-O'PAL. A variety of opal. Colours 

 white, grey, green, red, brown, blue, 

 rarely yellow. 



SEMI-OR'DINATE. In come sections, a line 

 drawn at right angles to, and bisected by, 

 the axis, and reaching from one side of 

 the section to the other. 



SEMIPAL'MATE, Lat. semi, half, and 

 paima, hand. In zoology, when the toes 

 are connected by a web extending only 

 half their length. 



SEMI-PELA'OIANS. In ecclesiastical his- 

 tory^ sect retaining some of the doctrines 

 of Pelagius. 



SEMI-PRO'TOLITE. The name given by 

 Kirwan to minerals partaking of the na- 

 ture of primary and secondary rocks: 

 rrfwras, first, and foQof , stone. It ought 

 to be henriprotolite. 



SEMI-CIUAD'RATE, ) An aspect of the pla- 



SEMI-QUAR'TILE. J nets, when distant 

 from each other half a quadrant. 



SEMI-QUA'VER. In music, a note of half 

 the duration of the quaver. 



SEMI-QDIN'TILE. An aspect of the pla- 

 nets, when distant from each other half 

 of the quintile, or 36. 



SEMI-SEX'TILE. An aspect of the pla- 

 nets, when distant from each other the 

 twelfth part of a circle, or 30. 



SEM'ISOSPIRO (It.). In music, a small 

 pause, equal to the eighth part of a bar 

 in common time. 



SEM'I-TONE. In music, half a tone ; an 

 interval of sound, as between mi and fa 

 in the diatonic scale, which is only half 

 the distance of the interval between ut 

 and re, or sol and la. It is the smallest 

 interval admitted in modern music. 



SEM'I-VOWEL. In grammar, a half- 

 vowel ; an articulation which is accom- 

 panied with an imperfect sound, as I, m, 

 n, which do not demand a total occlusion 

 of the mouth. 



SEMNOPITHE'CUS. The generic name 

 given by F. Cuvier to certain monkeys, 

 which differ from the long- tailed monkeys 

 (Cercopithectis, Erxl .), only by having an 

 additional small tubercle on the last of the 

 inferior molares. They inhabit eastern 

 countries. The best known is the Simia 

 neineeut, Lin., remarkable for its lively 

 and varied colouring. It inhabits Cochin 

 China. The S. nasica, Lin., of Borneo, is 

 remarkable for the extraordinary form of 

 its nose. 



SEMPERVI'RENT, Lat. sempervirens, ever- 

 green. Applied to plants whose leaves are 

 permanent throughout one, two, or more 

 years. 



SEMPERVI'VUM. The House Leek. An 

 extensive genus of plants. Dodtcandria 

 Dodecagynia. Name from semper, always, 

 and PICO, green. The British type is the 



common house-leek, or sengreien (8. ttc- 

 torum), a perennial. 



SEMCN'CIA. A Roman coin, one twenty-- 

 fourth of the Roman pound. 



SEN'ATE , Lat. seiiatus , assembly of elders. 

 The deliberative assembly of the Roman 

 people. In many modern republics, the 

 upper house of the national assembly has 

 been so called. 



SEN'ECA-ROOT, ) The root of the rattle- 



SEN'EQA-ROOT. I snake milk-wort (Poly- 

 gala Senega) , formerly much esteemed as 

 a specific against the poison of the rattle- 

 snake. It is used in decoction. See 

 SENEGA. 



SENE'CIO. Groundsel. An extensive 

 genus of plants. Syngenesia Polygamia 

 siiperflua. Name from senesco, to grow 

 old, because it has a greyish down upon, 

 it like the beard of an old man. There are 

 nine species natives of Britain, among 

 which are the common, wood, and 

 squalid groundsel, the common and the 

 marsh ragwort, or St. James's- wort, and 

 the bird's-tongue all herbaceous plants. 



SEN'EGA. A plant, a species of polygala, 

 so named because the Seneca or Sene- 

 gaw Indians use it against the bite of 

 the rattlesnake. See SENECA-ROOT. 



SEN'EGAL GUM. See ACACIA and GUM. 



SEN'ESCHAL. A French title, answer- 

 ing to that of high steward in England. 



SEN'NA. In the materia medica, the 

 leaves of the Cassia senna, an annual 

 plant, which grows plentifully, (and 

 best), in the valleys of Nubia, where it 

 is called Abyreyga. It grows also in 

 Arabia, and is imported thence into India, 

 under the name of S&na, and is imported 

 from Calcutta and Bombay under the 

 name of East India senna. 



SENSA'TION. "When an impression made 

 on the extremity of a nerve is communi- 

 cated to the sensorium, so as to excite 

 the consciousness of the mind, it is called 

 a sensation. When the impression is made 

 by the action of a foreign body on an ex- 

 ternal part, it is called an external sensa- 

 tion ; when it proceeds from some change 

 taking place within the living system, 

 and arising from its own actions, it is an 

 internal sensation. There are, however, 

 sensations belonging to neither of these 

 classes. The vehicles of impressions 

 giving rise to sensations, are the nerves: 

 the organs by which they are primarily 

 received, are termed the organs of the 

 senses. See SENSES. 



SEN'SES. The channels of communica- 

 tion by which the mind derives the ma- 

 terials of thought from the external 

 world, and the exercise of which depends 

 on the property of sensibility, modified by 

 particular organs to especial ends. Man 

 is usually considered to be endowed with 

 five senses: sicht, hearing, smell, taste, 

 and toueh To these Dr. Thomas Browne, 



