Rotation of Crops 



less exhausted. It is folly to invite guests 

 to a bare table. 



If the table were spread afresh, if manure 

 were again spread over the ground, it would 

 be a different matter, and the wheat would 

 do as well as ever. But it would be bad 

 economy ; for when a meal has been served 

 it is well to make all possible use of it. Be- 

 fore we go to fresh expense in manure we 

 will utilise to the utmost the expense already 

 incurred. Rover made a good dinner on 

 Jim's leavings, and the fowls did well on 

 something that was despised by Rover and 

 the cat. Let us follow the example of these 

 feeders, who have successively utilised the 

 remains rejected by the others. The wheat 

 has almost, or entirely, exhausted every- 

 thing that suits itself. But just as the 

 cowman Jim left the bone, the wheat has 

 left several substances which are excellent 

 food for others. To derive every advantage 

 from the first supply of manure, we must 

 find a guest of a different nature. This guest 

 may be the potato. The potato will find 

 plenty to live upon in ground where the 

 wheat would have starved, because its tastes 

 are quite different from those of the cereal. 



That makes two ; and we have sacks of 



217 



