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On the Economy of Machinery and Manufactures eBook

This eBook from the Gutenberg Project consists of approximately 313 pages of information about On the Economy of Machinery and Manufactures.

4.  The advantages which are derived from machinery and manufactures seem to arise principally from three sources:  The addition which they make to human power.  The economy they produce of human time.  The conversion of substances apparently common and worthless into valuable products.

5.  Of additions to human power.  With respect to the first of these causes, the forces derived from wind, from water, and from steam, present themselves to the mind of every one; these are, in fact, additions to human power, and will be considered in a future page:  there are, however, other sources of its increase, by which the animal force of the individual is itself made to act with far greater than its unassisted power; and to these we shall at present confine our observations.

The construction of palaces, of temples, and of tombs, seems to have occupied the earliest attention of nations just entering on the career of civilization; and the enormous blocks of stone moved from their native repositories to minister to the grandeur or piety of the builders, have remained to excite the astonishment of their posterity, long after the purposes of many of these records, as well as the names of their founders, have been forgotten.  The different degrees of force necessary to move these ponderous masses, will have varied according to the mechanical knowledge of the people employed in their transport; and that the extent of power required for this purpose is widely different under different circumstances, will appear from the following experiment, which is related by M. Rondelet, Sur L’Art de Batir.  A block of squared stone was taken for the subject of experiment: 

1.  Weight of stone 1080 lbs

2.  In order to drag this stone along the floor of the quarry, roughly chiselled, it required a force equal to 758 lbs

3.  The same stone dragged over a floor of planks required 652 lbs

4.  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

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