Messrs. Willcox & Gibbs depend upon a similar device shown in three
varieties to-night.

_Speed of Power Sewing Machines_.--The fastest practicable speed of a
machine worked by the foot appears to be 1,000 stitches per minute. Most
operators can guide the work at a much higher rate, especially in tailoring
or on long seams. The average speed upon such work is 1,200 stitches per
minute; but many lock-stitch machines are run at 1,500 and 1,800 per
minute, and even at much higher rates. There is always a limit to be
imposed upon speed by the guiding powers of hand and eye; it is this limit,
and not the capability of the machine, that confines the rate of driving.
Willcox & Gibbs' single thread machines are run in many instances at 3,500
stitches per minute. We have before us a single thread Singer machine
(appropriately named the "Lightning Sewer") and a Willcox machine, moving
at the enormous rate of 4,500 stitches per minute, and producing good work.
But it is doubtful whether such very great velocities can ever be
advantageously employed. Upon collar work, and in sewing boot uppers, the
rate seldom rises above 1,200 with advantage. If the machines be speeded
too high in any trade, the operator never uses the excess, and it only
proves a drawback. I seen the heaviest and hardest kind of navy boots
stitched at 1,500 to the minute upon Singer's lock-stitch machines. Wheeler
& Wilson's No. 10 D machine has been run by them, I am informed, as high as
2,500 to the minute. Loop-stitch machines, when well made, can be actually
run as high as 6,000, but 4,500 is, I believe, the maximum yet used for
this class of machine, even experimentally. There can be no doubt that
lock-stitch machines can be run as high as 3,000. The actual speeds of the
lock-stitch machines shown here upon the power stand average 1,300; those
of the chain stitch machines vary from 1,200 for the sack sewing machine to
4,500 for the small or single chain stitchers. Any of the latest styles of
either lock stitch or single thread machines can be run far faster than any