906 



THREAD MANUFACTURE 



steel mandril. A gold fillet is applied to the outside, in an annular space turned to 

 receive it, being fixed by pressure at the edges, into a minute groove formed on the 

 lathe. 



Thimbles are made in this country by means of moulds in the stamping machine. 

 See STAMPING OF METALS. 



THOAIXnriHX or THORIUM. A rare metal, discovered in 1828 by Berzelius 

 in the Norwegian mineral thorite, which contains about 57 per cent, of thorina, the 

 oxide of this metal, and where it is associated with the oxide of iron, lead, manganese, 

 tin, and uranium, besides earths and alkalis. None of the compounds of thorinum 

 find any use in the arts. 



THREAD XMEAXTDTACTITRZ:. The doubling and twisting of cotton or linen 

 yarn into a compact thread for weaving bobbin-net, or for sewing garments, is 

 performed by a machine resembling the throstle of the cotton-spinner. Fig. 1976 

 shows the thread-frame in a transverse section, perpendicular to its length, a, is the 

 strong framing of cast iron ; b, is the creel, or shelf, in which the bobbins of yarn I, I, 

 are set loosely upon their respective skewers, along the whole line of the machine, 



1976 



their lower ends turning in oiled steps, and their upper in wire-eyes ; c, is a glass rod 

 across which the yarn runs as it is unwound ; d, d, are oblong narrow troughs, lined 

 with lead and filled with water, for moistening the thread during its torsion ; the 

 threads being made to pass through eyes at the bottom of the fork e, which has an 

 upright stem for lifting it o\it without wetting the fingers, when anything goes amiss ; 

 f,f, are the pressing rollers, the under one g, being of smooth iron, and the upper one 

 h, of boxwood ; the former extends from end to end of the frame, in lengths com- 

 prehending eighteen threads, which are joined by square pieces, as in the drawing- 

 rollers of the mule-jenny. The necks of the under rollers are supported at the ends 

 and the middle, by the standards i. secured to square bases ,;", both made of cast iron. 



