1 12 THE OLIVER PLOW^BOOK 



a slanting cut. This also has a tendency to make 

 the plow pull lighter in draft than a plow with a 

 straight landside. 



These few illustrations serve to show that it is highly 

 important to select a plow bottom for handling the soil 

 the way it should be, and also that when any doubt 

 exists to consult a plow expert before a radical change 

 is made in bottoms. 



Generally speaking, the type of plow bottom that 

 does the best work pulls the hardest because the old 

 law that so much energy is required to produce a given 

 amount of work is applicable to plow bottoms. Less 

 power is required to break a clod into three parts than 

 into a million. The breaking of earth into finer particles 

 is highly important if the proper seed bed is to be 

 prepared. 



Tests have been made which show that mouldboards 

 curved to do the pulverizing require more energy or 

 power than the bottoms which break the soil into 

 clods. The four illustrations showing sectional views of 

 plowing are the results of a test made purposely to deter- 

 mine whether the plow bottom that did the best pul- 

 verizing pulled heavier than the one that did the inferior 

 grade of work. This test was made in a field of very 

 heavy clay and sand not in a loamy combination. It 

 had not rained for several weeks. All the tests were 

 made in the morning of the same day in order that there 

 should be as little change as possible in the moisture 

 content of the ground. The only difference in the plow 

 bottoms was in the shape of the mouldboards. Thus, the 

 condition for all the plows was the same, the only dif- 

 ferent contributing factor being the mouldboard. 



