

TEAK. WOOD TECHNOLOGY. 



TEAK-WOOD (tei-tunn yrimdia) ; one ot tin- 

 largest trees known, mid one <>t tin- mo-t interest- 

 ing, from the properties of the wood. It is refer- 

 icd to the natural family verlienan-a: The young 

 branches are quadrangular and jointed ; the leaves 

 opposite, ohovate and downy beneath, somewhat 

 declining, on young trees from one to two feet long, 

 and eight to sixteen inches in breadth. The flowers 

 are small, white and fragrant, disposed in widely 

 spreading terminal panicles. The calyx is toincn- 

 tose, and the corolla hardly longer than the calyx. 

 The fruit is a one-celled drupe. This tree abounds 

 in the extensive forests of Java, Ceylon, Malabar, 

 Coromandcl, &c., but especially in the empires of 

 Birmah and Pegu, from which countries Calcutta 

 and Madras draw all their supplies of ship timber. 

 The wood is light and easily worked, and, at the 

 same time, strong and durable. It is considered 

 superior to all others for ship building, and is, be- 

 sides, extensively used in the East in the construc- 

 tion of houses and temples. This tree has been 

 introduced into the British possessions in Indm, 

 and is now planted, with a view to timber, in the 

 mountainous parts of Bengal. Its cultivation has 

 also been recommended in the West Indies ; and 

 some circumstances seem to encourage the idea that 

 it will succeed beyond the tropics. The leaves 

 furnish a purple dye, which is employed for colour- 

 ing cottons and silks. 



TEAL. This name is given to some small spe- 

 cies of duck, resembling, in their habits and anato- 

 mical characters, the domestic species. Teal fre- 

 quent the fresh waters of the interior, living on 

 aquatic plants and seeds, and rarely visit the sea- 

 shore. The flesh is dry and difficult of digestion, 

 but, notwithstanding, is in great request. 



TEAR, AND LACHRYMAL ORGANS. The 

 limpid fluid secreted by the lachrymal glands, and 

 flowing on the surface of the eyes, is a little heavier 

 than water, and contains much pure soda, also 

 muriate, carbonate and phosphate of soda, and 

 phosphate of lime. The organs which secrete this 

 liquid are the lachrymal glands, one of which is 

 situated in the external angle of each orbit, and 

 emits six or seven excretory ducts, which open on 

 the internal surface of the upper eyelid, and pour 

 forth the tears. The tears have mixed with them 

 an arterious, roscid vapour, which exhales from the 

 internal surface of the eyelids, and external of the 

 tunica conjunctiva, into the eye. Perhaps the aque- 

 ous humour also transudes through the pores of the 

 cornea on the surface of the eye. A certain part 

 of this aqueous fluid is dissipated in the air ; but 

 the greatest part, after having performed its office, 

 is propelled by the orbicular muscle, which so closely 

 compresses the eyelid to the ball of the eye as to 

 leave no space between, except at the internal angle, 

 where the tears are collected. From this collection 

 the tears are propelled through the lachrymal canals 

 into the lachrymal sac, and flow into the cavity of 

 the nostrils, where they are partly thrown out, 

 partly swallowed. If the passage of the tears from 

 the eyes to the nose is disturbed, or prevented (e. g. 

 by a stoppage of the lachrymal duct), they flow 

 down the cheeks, and also collect in the lachrymal 

 sac, extend it, are here changed in their quality, and 

 cause an inflammation, which generally brings on 

 ulceration, and, if not attended to, even affects the 

 hones. This is the disease known by the name of 

 l-tchrymal fistula. To cure it, an operation is re- 

 quired, by which a new duct is formed for the tears 

 to enter the nose. The tears have no smell, but a 



saltish taste, as people \\lio wcrp perceive. The) 

 are of a t can-parent colour, and aqueous consistence. 

 The quantity, in its natural state, is just sullicicnt 

 to moisten the surface of the eye and eyelids ; but 

 from sorrow, or any kind of stimulus applied to the 

 surface of the eye, so great is the quantity of tears 

 secreted, that the puncta Idi-liri/tiuilin are unable to 

 absorb them. Thus the greatest part runs down 

 from the internal angle of the eyelids, in the form 

 of great and copious drops, upon the cheeks. A 

 great quantity also descends through the lachrymal 

 passage into the nostrils ; hence those who cry have 

 an increased discharge from the nose. The use of 

 the tears is to prevent the pellucid cornea from 

 drying and becoming opaque, or the eye from con- 

 creting with the eyelids. They prevent that pain 

 which would otherwise arise from the friction of 

 the eyelids against the bulb of the eye, from con- 

 tinually winking. They wash and clean away the 

 dust of the atmosphere, or any thing acrid that has 

 fallen into the eye. Weeping relieves the head of 

 congestions. 



TEASEL (dipsacuit). This plant bears a 

 general resemblance to the thistle, and might very 

 readily be mistaken for a compound flower ; but 

 each floret is provided with its calyx, and the four 

 stamens are not united. The corolla is tubular, 

 and divided into four lobes at the summit ; the 

 florets are disposed in large, oval, conic receptacles, 

 and are separated by long, projecting scales or 

 chaffs. The cultivated teasel (D. fullonum) has a 

 herbaceous, upright, prickly stem ; the leaves are 

 connate, oval-lanceolate, and likewise prickly be- 

 neath, on the principal nervures. The florets are 

 blue, and expand successively by zones. It has 

 been considered a variety of the wild teasel (D. 

 sylvestris), a common plant in many parts of Eu- 

 rope ; but it differs in having the scales or chaffs 

 more rigid, recurved, and forming a little hook at 

 the extremity. This conformation is peculiarly 

 suitable for raising the nap upon woollen cloths ; 

 and for this purpose the heads are fixed round the 

 circumference of a large, broad wheel, which is 

 made to turn round, and the cloth is held against 

 them, or they are set into flat boards like cards. 

 This plant is, in consequence, cultivated for manu- 

 facturing purposes, and has become an article of 

 considerable importance. The seeds are sown in 

 March, in well prepared, strong, rich land, broad- 

 cast, and at the rate of one peck to the acre. They 

 are hoed, like turnips, to a foot distance; and the 

 second year, in August, the heads are n't to cut. 

 They are sold by the bundle of twenty-five in each, 

 and the ordinary produce is 160 of such bundles to 

 the acre. 



TECHNICAL (from n^n, art) signifies, in 

 general, that which belongs peculiarly to art, or to 

 any branch of it in particular. A technical term is 

 an expression peculiar to an art or profession. In 

 the fine arts, the technical is contradistinguished to 

 the cesthetical, comprising every thing relating to 

 the material execution of works of art. 



TECHNOLOGY (from rt^, art, and x y f , 

 word, science) is the science which treats of the 

 arts, particularly the mechanical. Technology 

 may be divided into two kinds, a higher and lower, 

 of which the latter treats of the various arts them- 

 selves, and their principles, their origin, histoiy, 

 improvement, &c. ; the former, of the connexion of 

 the arts and trades with the political condition of a 

 nation, and the important influence which they 

 havo exercised ever since the mechanical ocnipa- 



