minute, and the larger
oatmeal stone 111 revolutions, but the smaller oatmeal stone and the
shelling stone revolve faster than this. At the time the indicator diagram
was taken, each pair of flour stones was grinding at the rate of 5 bushels
an hour; each pair of oatmeal stones about 24 bushels an hour; and the
shelling stones were shelling at the rate of about 54 bushels an hour. The
fanners and screen were also in operation.

696. _Q._--Have you any other case to enumerate?

_A._--I may mention one in which the power of the same engine was increased
by giving it a larger supply of steam. The engine when working with 8.65
horses power, gives motion to one pair of oatmeal stones of 4 feet 6 inches
diameter, and one pair of flour stones 4 feet 8 inches diameter. The
oatmeal stone makes 100 revolutions in the minute, and the flour stone 89.
The oatmeal stones grind about 36 bushels in the hour, and the flour stones
5 bushels in the hour. The engine when working to 12 horses power drives
one pair of flour stones, 4 feet 8 inches diameter, at 89 revolutions per
minute and one pair of stones of the same diameter at 105 revolutions,
grinding beans for cattle. The flour mill stones with this proportion of
power, being more largely fed, ground 6 bushels per hour, and the other
stones also ground 6 bushels per hour. When the power was increased to 18
horses, and the engine was burdened in addition with a dressing machine
having a cylinder of 19 inches diameter, the speed of the flour stone fell
to 85, and of the beans stone to 100 revolutions per minute, and the yield
was also reduced. The dressing machine dressed 24 bushels per hour.

697. _Q._--What is the power necessary to work a sugar mill such as is used
to press the juice from canes in the West Indies?

_A._--Twenty horses power will work a sugar mill having rollers about 5
feet long and 28 inches diameter; the rollers making 2-1/3 turns in a
minute. If the rollers be 26 inches diameter and 4-1/2 feet long, 18 horses
power will suffice to work them at the same speed, and 16 horses power if
the length be reduced to 3 feet 8 inches. 12 horses power will be required
to work a sugar mill with rollers 24 inches diameter and 4 feet 2 inches
long; and 10 horses power will suffice if the rollers be 3 feet 10 inches
long and 23 inches diameter. The speed of the surface of sugar mill rollers
should not be greater than 16 feet per minute, to allow time for the canes
to part with