ith the yield.

Messrs. Barrett, Exall, and Andrewes give the following table as
illustrative of the work done, and the fuel consumed by their portable
engines; but this must be regarded as a maximum performance:--

Number of | Weight of | Quarters of | Quantity of | Quantity of
Horse Power.| Engine. | Corn thrashed| Coals consumed| Water required
| | in 10 Hours. | in 10 Hours. | for 10 Hours
| | | | in Gallons.
------------|-----------|--------------|---------------|---------------
|Tons. Cwts.| | Cwts. |
4 | 2 0 | 40 | 3 | 360
5 | 2 5 | 50 | 4 | 380
6 | 2 10 | 60 | 5 | 460
7 | 2 15 | 70 | 6 | 540
8 | 3 0 | 80 | 7 | 620
10 | 3 10 | 100 | 9 | 780
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694. _Q._--In speaking of horses power, I suppose you mean indicator horse
power?

_A._--Yes; or rather the dynamometer horse power, which is the same,
barring the friction of the engine. At the shows of the Royal Agricultural
Society, the power actually exerted by the different engines is ascertained
by the application of a friction wheel or dynamometer.

695. _Q._--Can you give any other examples of the power necessary for
grinding corn?

_A._--An engine exerting 23-1/3 horses power by the indicator works two
pairs of flour stones of 4 feet 8 inches diameter, two pairs of stones
grinding oatmeal of 4 feet 8 inches diameter, one dressing machine, one
pair of fanners, one dust screen, and one sifting machine. One of the flour
stones makes 85, and the other 90 revolutions in the minute. One of the
oatmeal stones makes 120, and the other 140 revolutions in the minute. To
take another case:--An engine exerting 26-1/2 indicator horses power works
two pairs of flour stones, one dressing machine, two pairs of stones
grinding oatmeal, and one pair of shelling stones. The flour stones, one
pair of the oatmeal stones, and shelling stones, are 4 feet 8 inches
diameter. The diameter of the other pair of oatmeal stones is 3 feet 8
inches. The length of the cylinder of the dressing machine is 7 feet 6
inches. The flour stones make 87 revolutions in the