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TECH'NICAL, <n%*ixos, appertaining to 

 the arts: rt%vr,, art. A technical term 

 is one which is not in common use, but 

 belongs to some art, profession, science or 

 calling. 



TECHNOL'OGT, from rt%vi, art, and 

 Xyaj, word. Explanation of technical 

 terms. 



TECTIBRAN'CHIATA. An order of gaster- 

 opods, approaching the Pectinibranchiata 

 in the form of the organs of respiration, 

 and like them inhabiting the ocean. 

 Name from tectus, covered, and branchus, 

 the branchiae being more or less covered 

 by the mantle, in which a small shell is 

 generally contained 



TECTO'NA. The generic name of the 

 teak-wood tree or Indian oak. Pentan- 

 driaMonogynia. Name from nzrovixos, 

 from Tfv%&, to build, in allusion to the 

 use of the wood in ship-building, &c. 

 One species, a forest-tree of India, &c. 

 See TEAK -WOOD. 



TE DEUM. A hymn to be sung in 

 churches or on public occasions of joy : so 

 called from the first words of the Latin 

 version. 



TEETH are usually divided into three 

 classes : the itmsorcs or cutting-teeth ; 

 the canini or canine teeth , and the mo- 

 lares or grinders. The incisores are the 

 four teeth in the front of each jaw ; the 

 cunini or atspidati are the longest of all 

 the teeth, deriving their name from their 

 resemblance to a dog's tusk. The molares, 

 of which there are ten in each jaw, are 

 so called because from their size and 

 figure they are adapted for grinding the 

 food. The last grinder of each jaw, from 

 its coming latest, sometimes not appear- 

 in" till the individual is advanced in 

 life, is called dens sapientice or wisdom 

 tooth. 



TEE-TOTA.LLEHS. A whimsical denomi- 

 nation, assumed by those abstinents who 

 professedly eschew all liquors stronger 

 than tea and coffee, or who are pledged 

 to abstain wholly from spirituous liquors. 

 This is tee-totalism. The origin of the 

 word tee-total is not well ascertained. It 

 was formerly used by soldiers, &c., as a 

 slang term for total. " He was tee-totally 

 puzzled." "He got a tee-total milling" 

 (beating, flogging). " He was tee-totally 

 budged" (drunk). It probably originated 

 with some notoriously incorrect articul*- 

 tor, who instead of pronouncing total, at 

 once, said te-te-tee-total. Some, who are 

 apparently not aware that the word is old, 

 suppose it to be a corruption of tea-total, 

 the tee-totallers confining themselves to 

 tea and coffee. 



TEINDS. In Scotland, the same as tithes 

 in England. 



TEI'NOSCOPE, from nit*, to emtend, and 

 rxe*i*i, to see. An optical instrument 



for observing objects in a state of exten- 

 sion in one direction. 



TELAMO'NES, rXaia, I bear up. In ar- 

 chitecture, figures of men used for sup- 

 porting entablatures. 



TEI/EORAPH, from r^A.6, distantly, and 

 y^atf M> to write. A machine adapted for 

 communicating intelligence rapidly at a 

 considerable distance, by means of certain 

 signals previously arranged. Galvanic 

 telegraphs are now coming rapidly into 

 use, instead of the old plan of elevating 

 signals on towers, &c., to be seen and re- 

 corded at some other similar establish- 

 ment. The following will give some idea 

 of the nature of the galvanic telegraph : 

 if a magnetised needle be freely suspended 

 by a fibre of untwisted silk, it will place 

 itself in a direction nearly due north and 

 south ; and it will return with a certain 

 force to that direction if it be drawn aside 

 from it. When such a needle is suspended 

 within a coil of copper wire or ribbon, 

 the direction of the length of the coil co- 

 inciding with that of the needle, and if 

 one end of the coil be connected by a 

 wire of any length with a copper plate, 

 while the other end is connected by a si- 

 milar wire with a zinc plate, so soon as 

 the copper and zinc plates are immersed 

 together into a diluted acid, the needle in 

 the coil will change its direction, and 

 place itself across the coil. The needle 

 will then be more or less east and west, 

 instead of north and south. The instant 

 that the zinc and copper plates are taken 

 out of the acid, the needle returns to its 

 original position. This deviation of the 

 magnetic needle is caused by the copper 

 wire and coil being thrown into a pecu- 

 liar state by the electricity excited when 

 the copper and zinc plates are immersed 

 in the acid. The species of electricity 

 thus produced is known by the name of 

 galvanism ; and the copper wire and coil 

 which unite the zinc and copper plate 

 may be said to be galvanised. The . 

 greater the extent to which the wire and ; 

 coil are thus galvanised, the greater will 

 be the extent to which the needle placed 

 in the coil will deviate from its natural 

 position. The deviation of the needle is 

 therefore used as a measure of the amount 

 of galvanism ; and the needle and coil 

 thus constitute what is called a Galvano- ' 

 meter. It is this little instrument, the 

 galvanometer, or magnetic needle sus- 

 pended in a copper coil, which, in connec- 

 tion with a copper and zinc plate im- 

 mersed in weak acid, and called a galvanic 

 battery, forms a principal element in the 

 construction of every galvanic telegraph. 

 As has been already said, the wires by 

 which the coil of the galvanometer is con- 

 nected with the galvanic battery may be 

 ol any length, and as each wire btcuuiet 



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