170 CHRONICLES OF A CLAY FARM. 



whether wind, or water, or steam, be the driving 

 agent, the favourite motion is the vertically -circular. 

 The horizontal water-wheel is good, but extravagant, 

 and of limited application ; but it is worth mention- 

 ing as a singular exception. Where steam is employed, 

 vertical-circular action is almost universal. Instance 

 the steam-paddle, the screw-propeller, the common 

 fly-wheel, the locomotive, the circular saw, the drum 

 of the threshing-machine, the steam pump, and many 

 others that will occur to the recollection of the engi- 

 neer. When we plough the sea, by steam, we do it 

 with the circular blades of a paddle : why not the 

 earth ? When we cut wood into saw-dust by steam, 

 we do it with the revolving teeth of a circular saw ; 

 why not the clod into soil as fine, by the same mode 

 of action ? 



1 What has the laborious dragging of a plough to 

 do with steam-mechanism, whose mode of action lies 

 in rapid revolution, which applied behind your loco- 

 motive (which must travel forward on the hard soil), 

 could cut a trench a foot deep, and with its case- 

 hardened tines, rasp away the soil from the land side 

 to any pattern of fineness, as easily as a saw can cut 

 a board taking a moderate bite of six or eight feet 

 wide as it goes ' 



