Winnow. - Conformably to our promise (p. 339 of this vol.), we have procured an engraving of an improved winnowing machine, manufactured by Messrs. T. and J. PolPreeman, of Long-acre, London ; who have furnished us with the following account of its construction :
B, is a screw and plate, placed at the end of the hopper, marked 2, Fig. 2; the design of which is to regulate the supply of grain.
C, is a blast, the force of which may, by means of the Venetian-blind, 5, (Fig. 2) be varied, as occasion may require.
Fig. 2. - The frame marked 3, is calculated for the reception of the sieves ; where the corn is separated from the chaff, and passes down the screen. - 4, is the screen, which works with the machine, and answers every purpose, attained by the screens commonly employed for cleaning corn, after it has been divided from the chaff.
The apparatus here described, requires the attendance of three persons, namely, one to set it in motion ; a second to feed, or furnish a supply of grain; and a third, to clear away the corn, after it is freed from impurities. With such assistance, it will winnow 5 quarters of wheat per hour, or 6 quarters of barley and oats : it will likewise clean pease, beans, and coffee; so that it cannot fail to be peculiarly useful in the West Indies.
The working of this machine is very simple; so that, with a little practice, any person may understand its various parts, and the sieves proper for the corn to be winnowed. - Lastly, as different kinds of grain vary in quality, the blast should be adjusted accordingly, by means of the Venetian-blind (marked 5, in Fig. 2) ; to which a brass plate is affixed.