TOP 



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TOR 



mast, and projecting on all sides. It 

 serves to extend the shrouds. 



TOP ARMOUR. A rail extending the 

 width of the top of a ship, on the after- 

 side, supported by stanchions, and equip- 

 ped M-ith a netting. 



TO'PAZ. A pern ; different, however, 

 from the rMrct&iov of the Greeks, a name 

 derived from Topazos, an island in the 

 Ked Sea, where the ancients used to find 

 precious stones. The topaz passes from 

 pale wine yellow to yellowish white, 

 greenish white, mountain green, and sky 

 blue : from deep wine yellow into flesh 

 red, and crimson red. Sp. gr. 3'46 to 3'64. 

 The highly crystallised and transparent 

 varieties are termed precious topaz. The 

 finest varieties are obtained from the 

 mountains of Brazil, and the Uralian 

 Mountains ; and the topaz generally oc- 

 curs in primary rocks. General consti- 

 tuentsalumina, silica, and fluoric acid, 

 coloured with oxide of iron. 



TOPAZ'OLITE, from topaz, and Xtftos, 

 stone. A pale yellow sub-variety of gar- 

 net, so named because it resembles the 

 topaz in colour. 



TOP-CHAINS. Chains used in action, by 

 which the lower yard is hung, in case the 

 slings be shot away. 



TOP-CLOTH. In a ship, a large piece of 

 canvass, used to cover the hammocks, 

 which are lashed to the top when the ship 

 is prepared for action. 



TOP-GALLANT-MAST. The mast next 

 above the top-mast. On this are extended 

 the top- gallant- sails. 



TOPH. A word originally from the He- 

 brew. Used, in surgery, to denote (1) a 

 soft swelling on a bone ; (2.) a concretion 

 in the joints. It is also used, in minera- 

 logy, to designate any calcareous depo- 

 sition, resembling, in lightnessof texture, 

 the tophus, or material thrown out of 

 volcanoes, 



TO'PHET. A polluted, unclean place, 

 near Jerusalem, into which the Jews used 

 to throw dead carcases, &c. 



TOP-LAN'TERN. A large lantern, placed 

 in the after- part of a top in any ship 

 where an admiral's flag or commodore's 

 pendant is flying. 



TOP-MAST. The second division of a 

 mast, or that part next above the lower 

 mast. 



TOP'PING. In nautical language, the act 

 of putting one extremity of a yard higher 

 than the other. 



TOP'PING-LIFT. A large strong tackle, 

 Smployedto suspend or top the outer end 

 of a gaff, or of the boom of a mainsail, in 

 a brig or schooner. 



TOP-ROPE. In a ship, a rope to sway up 

 a top-mast, or top-gallant-mast, to fix it 

 In its place. 



TOP-SAILS. Large sails extending across 



the topmasts by the top-saii-yards above, 

 and by the lower yards beneath. 



TOP-TAC'KLE. In ships, a large tackle 

 hooked to the lower end of the topmast 

 top-rope, and to the deck, in order to 

 augment the mechanical power in hoist- 

 ing the topmast. 



TOHEUMATOL'OGT, from TO^UIAX, sculp- 

 ture, and ye/x,$a, I describe. The science 

 or art of sculpture , or a description of i t. 



TORMEN-TIL'LA. Tormentil or Septfoil. 

 A genus of indigenous perennial plants. 

 IcosandriaPolygynia. Name from tor- 

 menttttn, pain, because it was supposed 

 to relieve pain in the teeth. There are 

 two species; the officinal or upright, ami 

 the creeping. The root of the former is still 

 admitted into pharmacopeias, and ha* 

 been used as a substitute for bark in the 

 process of tanning, it being a powerful 

 astringent. 



TORMEN'TOR. In agriculture, an instru- 

 ment something like a harrow, but sup- 

 ported on wheels, and each tine is fur- 

 nished with a hoe or share, that enters 

 and cuts up the ground. 



TOKNA'DO, Sp. and Port, tornado, a re- 

 turn. A violent gust of wind, rising sud- 

 denly, and distinguished by its veering 

 round all the points of the compass, like a 

 hurricane. Tornadoes are usually accom- 

 panied by much thunder and rain, but are 

 of short duration, and have a narrow 

 compass. 



TORPE'DO. The Electric Ray, or Cramp- 

 fish. A subgenus of fish of the genus 

 Raia, Lin. Name Latin, from torpeo, to 

 benumb, on account of the peculiarly 

 powerful galvanic shock which the fish 

 communicates when touched. The body 

 is smooth, and the teeth small and sharp". 

 It is taken on the coasts of France and 

 England, and in the Mediterranean, in 

 about 40 fathoms water. The space be- 

 tween the pectorals, head, and branchiae 

 's fitted on each side with a peculiar ap- 

 paratus, formed of little membranous 

 tubes, placed close together like a honey- 

 comb, subdivided by horizontal dia- 

 phragms into small cells, filled with a 

 sort of mucus, and traversed by numerous 

 nerves, proceeding from the eighth pair. 

 It is in this apparatus that resides the 

 electric or galvanic power, which has 

 rendered the torpedo so celebrated. 



Ton R ICEL'LI AN . Pertaining to Torricelii , 

 an Italian philosopher, who discovered 

 the true principle of the barometer. The 

 tube of this instrument is named after 

 him the Torricellian tube; and the vacuuia 

 produced in such a tube by filling it with 

 mercury, and allowing it to descend till 

 it is counterbalanced by atmospheric 

 pressure, is called the Torricellian ta- 

 ciiiim. 



TUR'RID. Parched . forrirft.it, from fcrr** 



