DR. DAUBENY ON THE ROTATION OF CROPS, ETC. 

 The following; diagram will show the variations in the annual produce 



Beet. 



205 



12 3 4 5 



13. Cichorium endivia. 14. Mentha viridis. 15. Apium petrosel'mum. 



The three remaining crops, of Endive, Mint, and Parsley, were introduced into the 

 series, from a wish to have one representative at least of the principal of those natural 

 families, which supply us, with either plants useful for field or garden purposes, or 

 with any of the commoner weeds which intrude themselves into our fields, it being 

 conceived, that some interesting and useful results might be obtained, by watching 

 the effect of their root excretions on plants of the same or of a different tribe. 



Had it not been with a view to this theory, I should hardly have thought it worth 

 while to experiment upon plants, which appear to draw comparatively so little from 

 the soil, as the three now alluded to. 



The following, however, were the results obtained : — 



2 E 2 



