T U F 



to locality, beftow it on all calcareous rocks which poflefs 

 the grain, tiffue, and formation analogous to that of the tra- 

 vertine of Tivoli. If the ancient and modern Romans have 

 employed this itone in the mofl noble ftruftures, they have 

 but followed the examples of other people before them. 

 The temples of Paeftum, the moft ancient monuments that 

 are known after the pyramids of Egypt, were built with a 

 travertine formed by the depofition of waters which ftill 

 exift in that dillrift. This ftone, when long expofed to the 

 air, acquires a confiderable degree of hardnefs ; its colour 

 ifTumes a reddifli tinge pleafing to the eye, and which in no 

 fmall degree contributes to beftow on monuments of anti- 

 quity that majeftic charafter which is fo ilriking. Buch 

 juftly obferves, that tlie temples of ancient, and the churches 

 and palaces of modern Rome, would infinitely have lolt of 

 their grandeOr and majefty, if the bold genius which eredled 

 them had not met with fuch a material as travertine. Tliey 

 would have loft much of their folidity, if the formation of 

 tufa had not given rife to the difcovery of puzzolana. 

 The chance which coilefts in its vicinity the materials moit 

 fit for architefture, travertine and puzzolana, was not a 

 little happy for Rome. The mortar or cement which re- 

 fults from a mixture in juft proportion of that ferruginous 

 volcanic earth with lime, fo much furpaftes in hardnefs all 

 other known cements, that the exportation of puzzolana by 

 the Tiber and the port of Oftia is become a branch of trade." 



According to Ulloa, there are fountains of hot water "at 

 Guaniavelica, in South America, which form abundant beds 

 of ftone in a very (hort time, of fufficient hardnefs to be ufed 

 for building-ftone. Probably thefe fprings contain filiceous 

 as well as calcareous earth, filex having been found in the 

 waters of moft of the hot fprings ttiat have had their waters 

 analyfed. Siliceous tufa is depofited from the boiling 

 fprings in Iceland and the Azores, confifting almoft entirely 

 of pure filex. 



Bafaltic tufa confifts of fragments of the various kinds of 

 rocks denominated trap, cemented by a loofe argillaceous 

 bafis formed from decompofed bafalt. Sand-ftone frag- 

 ments, and even pieces of wood, fometimes occur in bafaltic 

 tufa. The maffes of ftone in this fpecies of tufa are from 

 the fize of a pea to feveral hundred weight. The larger 

 fragments generally occupy the lower part of the bed. 

 Sometimes beds of coarfe and fine tufa alternate with each 

 other, and fometimes they alternate with bafalt. The pofi- 

 tion of the beds is generally horizontal, their thicknefs vary- 

 ing from a few inches to feveral fathoms. A confiderable 

 portion of Arthur's feat near Edinburgh is compofed of 

 this rock. It occurs alfo in various bafaltic diftrifts. 



Volcanic tufa is formed by the earthy powder, improperly 

 called afties, which is thrown out of volcanoes, and fubfe- 

 qucntly confolidated by the agency of water. It is inter- 

 mixed with fragments of lava and fcoriae, lime-ftone, pumice, 

 and other rocks. The colour is brown or red, and fome- 

 times fpotted. Volcanic tufa is found of different degrees 

 of compaftnefs and hardnefs ; fometimes it forms a durable 

 but hght ftone, fuited for architeftural ufes. 



Beds of volcanic tufa alternate with bafalt and lava in 

 Iceland, and according to the account of fir G. Mackenzie, 

 hills of volcanic tufa occur in that country one thoufand 

 feet in height. It alfo conftitutes beds of great magni- 

 tude in fome of the mountains. Lava and beds of tufa, he 

 obferves, conftantly accompany each other in every part of 

 the ifland. The mud which iftues during volcanic erup- 

 tions in South America, forms beds of great extent, which 

 become hard by cxpofure to the air, and fprm a fpecies of 

 tufa. See Volcano. 



TUG 



TUFAN, in Geography. See Sipan. 



TUFARA, a town of Naples, in the province of Capi- 

 tanata ; 5 miles W. of Volturara. 



TUFECSI, a body of the fpahis, or horfe, in the fer- 

 vice of the grand fignor. 



TUFFE', in Geography, a town of France, in the 

 department of the Sarte ; 7 miles S.W. of La Fe»te 

 Bernard. 



TUFFEN, a town of Switzerland, in the canton of 

 Zurich ; 13 miles N. of Zurich. 



TUFFENBACH, a town of the duchy of Stiria ; 9 

 miles S. of Judenburg. 



TUFFO, in Botany, a name given by the people of 

 Guinea to a plant common in that country, and ufed in 

 decoftion to wafh fore eyes with. It is of the fun-flower 

 kind, and is called by Ve\\\er,fl6s folis Guineenfis folio fcabro 

 Jlore minore. It much refembles fome of the American fun- 

 flowers. Phil. Tranf. N= 232. 



TUFFOA, in Geography, a town of Africa, on the 

 Slave Coaft ; 40 miles W. of Aftbm. 



TUFFOONS, in Meteorology. See ToNQUIN. 



TUFT, in Botany and Vegetable Phyftology, technically 

 implies a head of flowers, capitulum, of which each indivi- 

 dual is not feffile, but elevated on either a fimple or fub- 

 divided partial ftalk, though all together compofing a denfe 

 roundifti mafs. Perhaps tuft would be better retained in 

 Englifli as fynonimous to fafciculus, in which fenfe it is 

 often praftically ufed, for any fmall number of flowers, 

 on ftiort aggregate or fubdivided ftalks, fpringing from 

 the bofoms of leaves, or the divifions of a panicle or 

 corymb. In like manner this term is applied, with more 

 laxity, to little bundles of leaves, hairs, &c. on different 

 occafions. 



TUFTED Duck, in Ornithology. See Tufted DuCK, 

 or FuLlGULA under Duck. 



Tufted Vetch, in Agriculture, a term commonly ap- 

 plied to a perennial fort of this plant, which is highly 

 deferving of cultivation by the farmer, for either meadow 

 or pafture land. It is frequently found mixed with the 

 other graffes, in rather moift ground. See Vetch, and 

 ViciA Cracca. 



TUFTONBOROUGH, in Geography, a town of New 

 Hampfhire, on the north fide of Winipifcogee hike ; 32 

 miles N. Concord. 



TUG, Bavin, in Agriculture, a fort of carriage ufed 

 in fome diftrifts for loading bavins or faggots, and fome- 

 times other kinds of field produce. It is fo made as to be 

 capable of carrying a hundred and fifty faggots, each four 

 feet in length, and three feet in girth, without being over 

 top-heavy, fo as to be liable to turn over in bad roads. 

 It is much ufed in the weald of Kent, and fome other 

 counties. 



TUGELOO, in Geography, a town of the ftate of 

 Georgia ; 95 miles N.W. of Augufta. N. lat. 34° 36'. 

 W. long. 83° 21'.— Alfo, a river of the ftate of Georgia, 

 one of the branches of the river Savanna, which joins the 

 Keowee ; 28 miles N.W. of Peterfburg. 



TUGGA, a town of Tunis ; 20 miles S.W. of Cairoan. 



TUGGALA, or Tegla, a town of Africa, in Kor- 

 dofan ; 150 miles W. S.W. of Sennaar. 



TUGGEN, a town of Switzerland, in the canton of 

 Glariis ; 5 miles S.W. of Utznach. 



TUGGURT, a town of Africa, in the kingdom of 

 Tunis ; 60 miles S.W. of Tunis — Alfo, a town ot Africa. 

 in Nigritia, capital of a diftria called Wadrcag ; 360 miles 

 N.E. or Tombuaoc. N. lat. 20° 30'. E. long. 6°. 



2 B 2 TUGGURTi 



