TEL 



706 



TEM 



galvanised throughout its whole length at 

 the same instant, there is no appreciable 

 interval of time between the connection 

 being made at the one end, and the needle 

 Seing affected at the other, at least for all 

 terrestrial distances. The effect of dis- 

 tance is not to diminish perceptibly the 

 rapidity with which the effect on the 

 needle is produced, but merely to lessen 

 the quantity of that effect. This latter 

 effect of increased distance, however, may 

 be compensated by increasing the thick- 

 ness of the wire, which forms the medium 

 of communication, or by making the gal- 

 vanometer more sensitive, and the battery 

 more powerful. By such means this pe- 

 culiar influence could be made sensible at 

 the greatest terrestrial distances. The 

 further improvement of this instrument, 

 and a more familiar acquaintance with its 

 use, may ultimately lead to connections 

 being made between the most distant 

 countries in the world for the transmission 

 of intelligence ; and posterity may per- 

 haps witness the receipt of news from 

 India, by means of a galvanic telegraph, 

 in as many minutes as there are weeks 

 now occupied in the conveyance of a 

 despatch. 



TEI.EOSAU'RVS. A new genus of fossil 

 saurians, thus named by M. Geoffroy St. 

 Hilaire, from rr.Xt or r?jA.es, and sauru*. 



TEL'ESCOPE, from TJ>.S, at a distance, 

 and trximca, to see. An optical instrument 

 employed in viewing distant objects, as 

 the heavenly bodies It assists the eye in 

 two ways ; first, by enlarging the visual 

 angle under which a distant object is 

 seen, and thus magnifying the object; 

 and secondly, by collecting and conveying 

 to the eye a larger beam of light than 

 could have been collected by the naked 

 organ, and thus rendering the object 

 more distinctly visible. Telescopes are 

 divided into two general kinds, refracting 

 and reflecting. A refracting telescope con- 

 sists of several lenses through which the 

 objects are seen by rays refracted by them 

 to the eye. A reflecting telescope, besides 

 lenses, has a metallic speculum within its 

 tube, by which the rays proceeding from 

 an object are reflected to the eye. The 

 forms of both sorts have been frequently 

 varied, and they are sometimes distin- 

 guished by the names of their inventors, 

 as the Galilean and Newtonian telescope ; 

 sometimes by the particular use for which 

 they are best adapted, as the land tele- 

 scope, the night telescope, the astronomical 

 ..elescope, &c. 



TELESCO'PIUM. The telescope. Acon- 

 strllanon situated south of the Centaur 

 and Sagittarius. It contains nine stars, 

 rll. except one, less than the fourth mag- 

 nitude. 



TE O'PICM HEH*CH. 7.t. 



Telescope. A new asterism, Inserted In 

 honour of Dr. William Herschel, the as- 

 tronomer. 



TELLER. An officer in the Exchequer 

 (in ancient records called tallier), whose 

 duty is to receive all sums due to the 

 Crown, andtogive the Clerk of the Pells a 

 bill to charge him therewith. There are 



four tellers in the Exchequer. 2. A 



person in a bank, whose business is to re- 

 ceive and pay money for bills, orders, &c. 



TELLI'NA. The simpin : a genus of 

 marine and fresh- water bivalve shells, 

 inhabited by a tethys. The shells of this 

 genus are known by the irregular fold on 

 the forepart ; in the one valve the fold 

 being convex, and in the other concave. 

 About 100 species are known, upwards of 

 20 of which are found in the seas of our 

 coasts. Some species are also found fossil 

 in alluvial deposits. 



TEL'LURETTFD HYDROGEN. A singular 

 elastic fluid, consisting of hydrogen hold- 

 ing tellurium in solution. It is soluble in 

 water, forming a claret-coloured solution 

 it combines with alkalies, and burns with 

 a bluish flame, depositing oxide of tel- 

 lurium. Its smell is strong and peculiar, 

 not unlike that of sulphuretted hydrogen. 



TELLC'RIC ACID. The peroxide of tel- 

 lurium which combines with many of the 

 metallic oxides acting the part of an acid, 

 and producing a class of compounds called 

 telhirates. 



TELLC'RIUM, from tellus, the earth. 1. 

 The name given by Klaproth to a metal 

 extracted from several Transylvanian ores. 

 It is of a tin-white colour, verging on 

 lead-grey, with a high metallic lustre, 

 has a foliated fracture, and is so brittle as 

 to be easily pulverised. It is oxidised and 

 dissolved by the principal acids. 2. Tel- 

 lurium is also the name of a machine for 

 illustrating the motions of the earth. 



TEL'LUROUS ACID. The protoxide of 

 tellurium, which, if precipitated from its 

 solutions by an alkali, carries down with 

 it a portion of the precipitate, forming 

 with it a compound termed a tellurite. 



TEM'PERAMEST, Lat. temperamenttim, 

 from tempera, to mix. 1. In the ancient 

 physiology, the different mixture of the 

 four cardinal humours, and the predo- 

 minance of one or the other, gave rise to 

 four distinct temperaments, viz., the san- 

 guine, the choleric, the phlegmatic, and the 

 melancholic. The constitution of every 

 individual was supposed to be conformed 

 to some one of those temperaments, or to 

 a mixture of two or more of them. To 

 the temperaments noticed by the ancients, 

 modern physiologists add a fifth, viz., 

 the nerrous. 2. In music, the adjust- 

 ment of the imperfect concords, In instru- 

 ments whose sounds are fixed, so a* to 

 transfer to them part of the music Of per- 

 fect concords. 



