120 COMBINED POETABLE ENGINE AND WINDING DKUM. 



This table (which may be modified according to circum- 

 stances) shows that when an area exceeding 7U to 100 acres 

 is ploughed annually, it is more economical to use a double- 

 effect drum hauling a balance-plough. We will have an 

 opportunity later on of comparing these figures with those of 

 the steam winding drum engine (Fowler) often used by con- 

 tractors. - 



