Hoisting Wheels, a Mile-Gauge Gear, Sums, and Rain-Light
A treadwheel, tackle, a 12-mile gear train, columns of multiplication, and light through rain
Two mounted sheets crowded with mechanisms and calculation. The left sheet studies lifting gear: a vaned wheel of 11 rods, a stepped hoisting wheel with counterweights that makes two contrary motions and so needs two servants, and a treadwheel a man walks on, judged safer trodden from the outside than the inside; a gear note sets sixty teeth to one pinion tooth so a wheel turns once in 12 miles. Down the margins run a rule for extracting roots and long columns of multiplication, and lead-drawn circle figures accord with the scholarly tags on doubling the surface, the circle and the lune. The right sheet adds pulley-tackle held fast by a candle-loop, an endless screw, and a note on seeing the sun's redness and the rain through interposed clouds and waves.
On this page
A stepped wheel with two contrary motions
Here one rope descends without weight while the other rises with the weight, the rope fixed at the middle of the axle's length. Because the wheel makes two contrary motions it needs two servants; the mangano wheel goes backwards and forwards.
A treadwheel safer walked from outside than inside
The wheel walked on the outside is more useful than the one walked inside: in one there is danger of death, in the other safety of life. If the wheel ran back with fury, whatever was inside would be thrown about, whereas the driver outside need only lift his foot and stay on the platform holding the rope.
A gear train turning once in twelve miles
Make sixty teeth per wheel and one tooth per pinion, and the second wheel will make one full turn in 12 miles, a train for measuring distance travelled.
Tackle held fast by a candle-loop
A loop made of the candle b a, beneath the taut rope, n, holds the ropes of the tackle-blocks so that they do not run, even though the heavy load joined to the tackle hangs suspended in the air.
Extracting roots and columns of multiplication
A margin rule: take the root of the number of which you want the thousands, the root of 3000 being left unfinished. The rest of the sheet is filled with columns of multiplication and figuring (55 and 50, 50 and 60, and further products).
The sun's redness and rain seen through clouds and waves
Within the space of the rain the redness of the sun is seen, that is, of the clouds interposed between the sun and the rain. The waves interposed between the rain and the eye never show the eye the image of the rain's darkness, because the side of the wave is neither seen nor sees the rain.