TRA 



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TRA 



part of the interior of the body, and thus 

 remedy the want of circulation. 



TRACHEA'RI.V. An order of Arachnides, 

 characterised by radiated or ramified tra- 

 chea, so that the organs of respiration 

 receive air through two stigmata, in the 

 absence of an organ of circulation. The 

 order comprises the Pseudo-scorpiones, 

 Pycnogonides, and Holetra. 



TRACHEOCE'LE, from trachea, and zrf.v!, 

 a tumour. An enlargement of the thy- 

 roid gland : bronchocele or goitre. 



TRACHEOT'OM Y, from trachea, and TI/AVU, 

 to cut. See BROXCHOTOMY. 



TRACK I'srs. The name given by Lin- 

 naeus to a genus of acanthopterygious 

 fishes of the percoid family. There are 

 several species from the Atlantic, &c., of 

 which the dragon- weever (T. draco ,Lin.) , 

 is best known. The flesh is esteemed. 



TRA'CHYTE, from TOK^US, rough. The 

 name of a kind of volcanic porphyry, 

 which usually contains crystals of glassy 

 felspar, and is exceedingly rough to the 

 touch. 



TRAC'TION, from traho, to draw. In 

 practical mechanics, the amount of power 

 necessary to overcome the resistance to 

 a carriage upon a road ; a boat upon a 

 canal, &c. The power applied is termed 

 the tractive power. 



TRAC'TORS, METALLIC. Small bars of 

 metal, supposed to possess certain mag- 

 netic powers of curing painful affections 

 and tumours, by being drawn over the 

 affected parts. 



TRAC'TORY or TRAC'TRIX, Lat. traho, I 

 draw. In geometry, the curve having the 

 property that the tangent is always equal 

 to a given line. 



TRADE-WINDS. The monsoons or peri- 

 odical winds between the tropics, sup- 

 posed to favour trade. 



TRAG'ACAKTH, from racfyo;, a goat, and 

 axa-tOo;, a thorn. A species of gum, the 

 produce of the Astragalus tragacantha, a 

 thorny shrub, which grows in Persia, 

 Crete, &c. See GUM. 



TRA'GEDY, r^aycaoiot- A dramatic poem 

 representing some signal action, per- 

 formed by illustrious personages. A tra- 

 gedy must necessarily have a fatal issue, 

 and commonly one or more of the drama- 

 tis personae is a villain, by whose machi- 

 nations the catastrophes are brought 

 about. 



TRA'GICL-S. A muscle of the ear which 

 pulls the tragus forward. 



TRAG'US. In anatomy, the small carti- 

 laginous eminence at the entrance of the 

 external ear. 



TRAJEC'TORY, from trajectus. A curvi- 

 linear path described by a body, as the 

 orbit of a comet. 



TRAM. A local name given to coal- 

 Wtggousin the neighbourhood of New- 



castle-upon-Tyne : hence the word tram- 

 way was given to the road prepared to 

 receive them. 



TRAM'MEL. A sort of large net either 

 for fishing or catching birds. 



TRAM'MELS. 1. In mechanics,* joiners 

 instrument for drawing ellipses. One part 

 consists of a cross, with two grooves at 

 right angles ; the other is a beam carry- 

 ing two pins, which slide in those grooves, 



and also the describing pencil. 2. A 



kind of shackles for a horse. 



TEAM' ROAD, \ A plate-railway. A de- 



TRAM'WAY. j scription of rail way, con- 

 sisting of narrow track-plates, or rails of 

 wood or iron, the same being prepared to 

 receive the wheels of carriages, or trams, 

 as waggons were formerly called, where- 

 by the transit of the latter is much fa- 

 cilitated. 



THAXSCEN'DENTAL, from trans, beyond, 

 and scando, to climb. Surpassing ; rising 

 above. In geometry, a transcendental 

 curve is one which cannot be defined by 

 any algebraic equation. Transcendental 

 quantities are indeterminate ones, which 

 cannot be expressed by any constant 

 equation. 



TRAN'SEPT, from trans and septum. An 

 open passage across the body of a church, 

 in the direction of north and south, either 

 on the eastern or western side of the 

 nave, and sometimes on both. 



TRASSFU'SION, from trans and fundo. 

 The transmission of blood from the veins 

 of one living animal into those of another, 

 by means of acanula; an operation which 

 has often been performed with success 

 and singular advantage on the human 

 subject. 



TRAN'SIT, Lat. transitus, from trans, be- 

 yond. In astronomy, the passing of one 

 heavenly body over the disc of another 

 and larger one, as Mercury and Venus 

 over the face of the sun. The reverse, or 

 the passage of the small body behind the 

 larger body, is an occupation. 



TRAN'SIT-IN'STRUMENT. A telescope 

 formed at right angles to a horizontal 

 axis, which axis is so supported that the 

 line of collimation may move in the plane 

 of the meridian. This instrument is used 

 for observing the transits of Venus ana 

 Mercury over the discs of the sun, and a 

 modification of it, bearing the same name, 

 is employed in the formation of tunnels, 

 for the purpose of ranging the shafts 

 straight together. 



TRANS'IT ION ROCKS, series or formations. 

 See ROCKS. 



TRAJJ'SITIVE, Lat. transitivus. In gram- 

 mar. A verb transitive is that which 

 signifies an action, conceived as having 

 an effect upon some object. 



TRAXSLC'CENCY, from trans, through, 

 asd luceo, to shine. A term used in min- 

 nalogy.Jte. to express the property wbicl 



