The same stone placed on a platform of wood, and dragged over
a floor of planks, required 606 lbs
5. After soaping the two surfaces of wood which slid over each
other, it required 182 lbs
6. The same stone was now placed upon rollers of three inches
diameter, when it required to put it in motion along the floor of
the quarry 34 lbs
7. To drag it by these rollers over a wooden floor 28 lbs
8. When the stone was mounted on a wooden platform, and the same
rollers placed between that and a plank floor, it required 22 lbs
From this experiment it results, that the force necessary to
move a stone along
Part of its weight
The roughly chiselled floor of its quarry is nearly 2/3
Along a wooden floor 3/5
By wood upon wood 5/9
If the wooden surfaces are soaped 1/6
With rollers on the floor of the quarry 1/32
On rollers on wood 1/40
On rollers between wood 1/50
At each increase of knowledge, as well as on the contrivance
of every new tool, human labour becomes abridged.
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