T H R 



to the (hock : though, in fome counties, they only reckon 

 twelve (hocks to the thrave. 



King AtheKlan, anno 923, gave by charter, to St. John 

 of Beverley, four thraves of corn for every plough-land in 

 the Eaft Riding of York(hire. 



" Ya fou threve be heaven king, 

 Of ilka plough of eft riding." 



THRAUPIS, in Ornithology, a name given by many 

 autliors to the bird more commonly called citrinella. 



THRAUSMA, a name given by the ancients to a kind 

 of gum ammoniacum, which was drier than the common, and 

 more eaiily crumbled to pieces. 



THRAUSTOMICTHES, m Natural Hi/lot y, the name 

 of a genus of compound earths. The word is derived from 

 the Greek 9j,oti/cro;, brittle, and fjm^u:, mixt. 



The bodies of this genus are loams compofed of fand 

 and a lefs vifcid clay, and are therefore of a friable or 

 crumbly texture. 



The earths of this genus arc generally ufed to make bricks ; 

 and there are fcveral fpecies of them. Hill. 



THREAD, in the Linm ManufaBure, a fmall line or 

 twill of flax, the weaving of which compofes cloth. There 

 is a (Ironger kind made ufc of to few the feams of linen gar- 

 ments, or to mend them. The fame term is applicable to 

 cotton or wool. See Spinning. 



Thread, fays an eminent French writer (Pajot des 

 Charraes), bleached by the oxygenated muriatic acid, may 

 be ufed by the fempftrefs with much greater fpeed and briflt- 

 nefs than thread of the fame quality bleached in the lield ; it 

 is lefs brittle, and may be ftruck much more effe&ually home 

 to its place in weaving, and does not move afterwards. This 

 information, he fays, was received by him from impartial 

 and unprejudiced manufafturers. 



The thread of the Laplanders is very fine, white, and 

 f^ong, but it is of a very dilTerent natuce from our's ; they 

 know nothing of flax or hemp, nor of any other plant whofe 

 ftalks might fupply the place of thefe in making thread, but 

 their's is made of the finews of the rein-deer. 



They kill of thefe animals a very great number continu- 

 ally, partly for food, partly for the fliiiis, which they ufe in 

 clothing themfelves, covering their huts, and on many other 

 oecafions ; the fmews of all they kill are very carefully pre- 

 ferved, and delivered to the women, whofe province it is to 

 prepare this necelTary matter. They beat the finews very 

 well, after having (ieeped them a long time in water, and 

 then they fpin them out. 



The thread they thus make is of any degree of finenefs 

 they pleafe ; but it is never any longer than the finew from 

 which it is made. They ufe this in fewing their clothes, 

 (hoes, gloves, &c. and the trappings of their rein-deer. The 

 threads of the fame (inew are laid up together, and are all of 

 a length ; and as the di(ferent finews alford them very different 

 leTigths, they accordingly pick out fuch as the prcfent ufe 

 requires, both in regard to length and finenefs. This fort 

 ' of thread is made with much more labour than our's ; but it 

 is greatly fuperior to it on many occafious, where ftrength is 

 rither required than beauty. 



Thefe people have, befides this, a way of making a fort of 

 yarn of (heep's wool, which they weave into garters and a 

 fort of ribbands, ufed by way of ornament ; but they place 

 no value on it, becaufe of its want of llrength. Scheffer's 

 yi\k. Lapland. 



Thread, in Botany, is underftood cif thofe capillamcnts 

 ufiially found in the middle of flowers, as in the )ily, tulip, 

 Vol. XXXV. 



T H R 



rofe, &c. There are two kinds ; thofe which fupport apices, 

 are particularly called Jlamina ; and tlujfe which have none, 

 pijlilla. 



TiiKKAi), GolJ. See Gold. 



TurtKAD, rirgin's. See Virgin. 



TiiKKADs, y//V, a term ufed by fome to exprefs thofe fine 

 long white filaments, or thready fubftances, which we meet 

 with in vaft numbers floating about in the air in Auguft and 

 September. 



The world has been much perplexed about the generation 

 of thefe, till it was known that they were the work of fpi- 

 ders, and that they fervcd thofe creatures to move from 

 place to place by. They are long, downy, and very foft, 

 and though they hold together when untouched, they ftick 

 to the fingers in handhng, and eafily break with a fight 

 touch. 



The general method of thefe creatures fpinning and 

 weaTing the webs, is by letting down the thread, then draw- 

 ing it after them, and fo difpofing it as they think proper ; 

 but in the midft of their work of this fort, if they are clofely 

 obferved, they will be fomctimes found to defift, and turning 

 the tail to the contrary way of the wind, they will emit a 

 thread with great violence, no lefs than that with which a 

 jet of water is difcharged from a cock. In this manner 

 they continue darting forth the thread, which the wind 

 takes, and carrying it forwards, it foon becomes many yards 

 long. Soon after this the creature will throw herfelf off 

 from the web, and trulling herfelf to the air with this long 

 tail, will afcend fwiftly, amd to a great height with it. The 

 fragments of thefe lines, or the whole lines, and the fpiders 

 attached to them, though unobferved, make thefe air-threads, 

 and the ufe nature deftines them for, is evidently the wafting 

 of the creature along the air, and giving it an opportunity 

 of preying on gnats, and many other i.nfefts that inhabit 

 the air, out of the re^ch of thefe creatures by any other 

 means. 



When the threads are newly fpun, they are always fingle, 

 and ai-e generally feen afcending higher and higher in the 

 air ; but when they are feen coming down, they are found 

 fometimes compofed of three or four others, and either 

 without any fpider at the ends, or with two or three, or 

 more. It is plain that this happens from the meetin-g of 

 thefe threads one with another in the air, and their tangling 

 together ; and this incommodes the creatures, and brings 

 them down. 



Thefe are what fill the air with the loofe threads we fee 

 in autumn ; and as thefe foon entangle together, and bring 

 one another down, it is no wonder that they are more fre- 

 quent in the lower regions of the air, than thofe with the 

 fpiders adhering to them, which ufually rife to great heights, 

 and fuftain themfelves there. And hence the origin of the 

 threads was much perplexed among the enquirers, becaufe 

 they were found without any mark of the animal to which 

 they owed their exiftence. The bufinefs of feeding is not 

 all the ufe of thefe threads, but the creatures evidently fport 

 and amufe themfelves by means of them, floating about in 

 the air, and changing height and place at pleafure. 



When a fpider has once raifed itfclf from the earth in 

 this manner, it does not defcend always on the fame thread 

 it arofe by, but draws that up at times, and winds it up 

 into a hank with its fore -feet, and darts out another by way 

 of fupport ; and the new thread is made more or lefs loijg, 

 as it is intended for a higher or lower flight. Philof. TranC 

 N'so. 



Thread of Glafs may be obtained of indefinite minute- 



nefs by means ol the blow-pipe. When no thicker than 



4 C fiii9 



