130 THE OLIVER PLOW BOOK 



share, as by the scouring qualities of the metal which 

 enter into its construction. 



As a matter of fact, tests in draft of plows have been 

 made in the agricultural departments of universities. 

 These fsts have shown that chilled plows are lighter in 

 dn 



fo process has yet been invented whereby steel can 

 tempered hard enough to prevent sand and stones 

 from deeply scratching the surface. Any farmer who has 

 land that is sandy in places knows, if he uses a steel 

 plow, that it refuses to scour after leaving the sandy 

 parts and enters the black or sticky land. This is 

 caused by the sand scratching the steel, leaving a feather 

 edge that ruins the dirt polish and makes an obstruction 

 to stop the shedding of the dirt. 



Anyone who has never had this feature called to his 

 attention can observe the phenomenon by examining 

 his plow the next time he plows a piece of land in that 

 condition. This peculiarity of steel makes a steel plow 

 an exceedingly poor implement to use in any soil that 

 has sand, gravel or stones in it, because the plow wears 

 out too soon. It is like using a razor to sharpen lead 

 pencils too costly. 



There is a type of land that steel plows turn to good 

 advantage and much better than chilled plows can, in 

 fact, where chilled plows will not work at all. Light 

 soils, loams free from sand, gravel, or stones, and black, 

 waxy dirt can be handled most successfully with the 

 steel plows, because they have in them the properties 

 necessary to make the dirt polish on the mouldboard 

 without scratching it. Wherever this condition prevails, 

 steel plows are the most successful, but when grit is 

 present the wear on the thin layer of hard steel on the 



