LACE MANUFACTURE.

737

the web. The warp threads stand in the positions a a, a' a', and a" a "; the one half°f the weft proceeds in the direction b b, b' b', and b" b "; and the second crosses the

first by running in the direction c c, 01c' c', towards the opposite side of the fab-ric. If we pursue the path of a wefithread, we find it goes on till it reachesthe outermost or last warp thread, which iltwists about; not once, as with the others,but twice; and then returning towards theother border, proceeds in a reverse direc-tion. It is by this double twist, and by thereturn of the weft threads, that the selvageis made.

The ordinary material of bobbin-net istwo cotton yarns, of from No. 180 to No.250, twisted into one thread; but some-times strongly twisted single yarn has beenused. The beauty of the fabric dependsupon the quality of the material, as well asthe regularity and smallness of the meshes.The number of warp threads in a yard inoFta* 1 * 1 is *" rom t0 > which is equivalent to from 20 to 30 in an inch. The sizeth * n cannot be exactly inferred from that circumstance, as it depends partly uponfro ^Nue faction of the threads. The breadth of the pieces of bobbin-net variesMde 6< ^ n = s a quarter of an inch, to webs 12, or even 20 quarters, that is, 5 yards

Ca ]?°j ) i ) iu-n e t lace is manufactured by means of very costly and complicateu machines,tha ™ f rain zs. The limits of this Dictionary will admit of an explanation of no morero n ihc general principles of the manufacture. The threads for crossing and twistinggas^ l * le war P, being previously gassed, that is, freed from loose fibres by singeing withgro’ . W ’ 0un 'J round small pulleys, called bobbins, which are, with this view, deeply°ved in their periphery. Mgs. 610,611 exhibit the bobbin alone, and with its carriage.

611

\v 0an t ] le se ction of the bobbin a, fig. 610, the deep groove is shown in which the thread istuddl The bobbin consists of two thin discs of brass, cut out in a stamp-press, in thean i n f of eac b of which there is a hollow space c. These discs are riveted together, leavingin th e erVa * between their edge all round, in which the thread is coiled. The round holein 0r( j Centre > lbe Rttle notch at top, serves for spitting them upon a feathered rod,th e bobty° ** e w ilh thread by the rotation of that rod in a species of reel, called%urei . ruling machine. Each of these bobbins (about double the size of theiron fra 1S lnsertet l into the vacant space g , of the carriage, fig. 611. This is a smallborder 0 f"ti < ’ a ' S ° d . ouble the size of the figure), which, at e e, embraces the groovedTh; s . tbe bobbin, and by the pressure of the spring at /, prevents it from falling out.from gi v | n f s< jT r . es likewise to apply sufficient friction to the bobbin, so as to prevent ite, hploved * * ts tbreac l at g by its rotation, unless a certain small force of traction bofile carriatf^n 11 tbrea<b The curvilinear groove h h, sunk in each face or side ofinterval vf ?’ “ as tbe depth shown in the section at h. This groove corresponds to theplaced and T ee P tbe tee th of the comb, or bars of the bolt, in which each carriage is111 Plan and aS movemen t. A portion of that bolt or comb is shown at a, fig. 612,SUc h coinhs 0n f i, a nifcular bolt machine at b, in section. If we suppose twoapart, to let °th . , ce< ^ w ith the ends of the teeth opposite each other, but a little

ups, we shill a 6 Warb .j ea ds be stretched, in one vertical plane, between their ends orave an idea of the skeleton of a bobbin-net machine. One of these two47