Seel. VII. Agriculture and Vegetation. 33 



SECT. VII. 



Of till. 



FARMERS call thofe foils til/, which 

 have a reddifh, gray, or yellowifli co- 

 lour, are poor, will bear nothing, nor can 

 be fertilized fo eafily or fpeedily as the for- 

 mer foils. Sometimes they render all at- 

 tempts fruitlefs. This icil muft, therefore, 

 not only contain no vegetable food, but it 

 muft often contain a vegetable poifon; elfe 

 it would always become fruitful by the ap- 

 plication of comports. What this poifon is, 

 muft be the lubjecl of our prefent inquiry ; 

 for unlefs we know it, we cannot know 

 whether there is a remedy for it or not. 



THE following experiments were per- 

 formed on iome of this unfruitful earth 

 mown me by an experienced farmer. 



Exp. 12. It efFervefced vifibly with vine- 

 gar and oil of vitriol diluted with water, 

 D but 



