otation of any particular bobbin or "cheese"
when an end or thread belonging to that "cheese" fails or breaks,
leaving the needles or detector wires. All the threads--from two to six
in number--belonging to one "cheese" are combined to form one loose rope
or thicker thread.

Image: FIG. 36.--Quick traverse winding frame.

It ought to be explained that the term cheese is applied to the kind of
bobbin of yarn which is formed upon this particular machine, one or two
being placed as shown on the frame work.

=Doubling Machine.=--The machine just described does not put any twist
into the thread, although twisting is a process which is absolutely
indispensable for the proper combination of the several single threads
so as to produce a strong doubled thread.

The twisting operation is therefore performed on the machine illustrated
in Fig. 37, and termed the "Ring doubling machine."

In the creel of this machine are placed the cheeses formed on the
winding machine, and the threads are conducted downward and usually
under a glass rod in trough containing water, as the addition of water
helps to solidify the single threads better into one doubled thread.
From the water trough the threads are conducted between a pair of
revolving brass rollers which draw the threads from the cheeses and pass
them forward to the front of the machine. Here each doubled thread
extends downwards and passes through a "traveller" upon the bobbin.

This machine is a modification of the ring spinning frame previously
described and therefore does not call for detailed treatment at our
hands.

The two machines are practically identical in principle, the chief
difference being that in the doubler there are no drawing rollers, as
the cotton is not attenuated in any degree at this stage.

Other differences consist in having larger "travellers" and "rings" and
"spindles," and in a different kind of bobbin being formed.

Image: FIG. 37.--Ring doubling machine.

At the doubling mill these threads are submitted to finishing processes,
by which they may be polished and cleared and finally wound upon small
bobbins or spools ready for the market, as seen in Fig. 2.

A fair proportion of the very best yarns are utilised in the manufacture
of lace and to imitate silk. Such yarns are usually passed through what
is termed a "gassing" machine. In this process each thread is passed
rapidly several times through a gas flame usually emanating from a
burner of