nted by a Frenchman of
Alsace named Heilmann. The patent was issued in 1845. Now there are on
the market other machines, both English and American, similar in
principle but improved in many ways.

[Illustration: _Revolving flat cards_]

The first of these preliminary processes is that which is done by the
sliver-lapper. The slivers from 14 to 20 cans are drawn along
side-by-side, passing between three pairs of drawing rollers which will
be described later. From the drawing rollers the slivers now reduced in
size, pass between two pairs of calendar rollers from which they emerge,
not as a sliver, of course, but once more as a lap about a foot wide.
These laps are usually passed to a ribbon lapper, where six of them are
placed end-to-end, and unrolled simultaneously, passed between four pairs
of drawing rollers, and then superimposed, one upon the other, and,
calendered once more, issued as a lap a little less than a foot wide.
This process may be repeated as many times as the quality of the yarn
desired may require, for each drawing process served to straighten the
fibers and so to render the thread more even and capable of finer
spinning.

Combing is exactly what its name implies. The lap is actually raked by a
fine-tooth comb with needle-like teeth of steel ranging from 16 to 90 per
inch. This involves breaking the lap again and the intricacy of the
comber rests in the mechanism which it employs for joining the separated
ends.

[Illustration: _Cross-section diagram of revolving flat card_]

Six or eight laps go through the machine at once, and the product is
combined, condensed, formed into a continuous sliver, and deposited once
more into cans. The process is not a fast one at best, and the chief
contribution of American inventors is in the direction of speed. Each nip
combs only 4/16 to 4/10 of an inch of fiber. The Heilman machine made
about 85 or 90 nips per minute. The American improvement makes 130 to
135. The width of the lap in the American machine is likewise increased,
and the saving in labor, therefore, is considerable. English improvements
have been in the same direction, the resultant saving being almost as
great.

[Illustration: _Ribbon lappers_]

Though many of the processes already described might be called drawing,
in a sense, insomuch as they involve a continual lengthening and
straightening of the lap or sliver, yet drawing in the strictest sense
has not yet begun. It may be done only once,