CONSTRUCTION OF MACHINES,

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Chap. 11.]

into the hopper, which answers very well; hut wherethere is room a hopper-boy is preferable.

article 98.

OF A GRAIN CONVEYER.

This machine has been constructed in a variety ofways; the following appears to be the best; namely:First, make a round shaft, 9 inches diameter; and then,to make the spire, take strong sheet-iron, make a pattern3 inches broad, and of the true arch of a circle; the dia-meter of which (being the inside of the pattern) is to be12 inches; this will give it room to stretch along a 9 inchshaft, so as to make a rapid spiral, that will advanceabout 21 inches along the shaft every revolution. Bythis pattern cut the sheet-iron into circular pieces, andjoin the ends together by riveting and lapping them, soas to let the grain run freely over the joints; when theyare joined together they will form several circles, oneabove the other, slip it on the shaft, and stretch it alongas far as you can, till it comes tight to the shaft, and fas-ten it to its place by pins, set in the shaft at the back sideof the spire, and nail it to the pins: it will now form abeautiful spiral, with returns, 21 inches apart, which dis-tance is too great; there should, therefore, be two or threeof these spirals made, and wound into each other, and allput on together, because, if one be put on first, theothers cannot be got on so well afterwards; if there bethree, they will then be 7 inches apart, and will conveywheat very fast. If these spirals be punched full ofholes like a grater, and the trough be lined with sheet-iron, punched full of small holes, it will become an ex-cellent rubber; will clean the wheat of the dust and down,that adhere to it, and supersede the necessity of anyother rubbing machine.

I lie spirals may also be formed with either wooden or

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