1830 



RURAL ECONOMICS 



Table II. — Production of vines [chronological series). 



(i ) Old vines replaced by runners at 40 years with a consequent increase of production. 



The values of the ordinates corresponding to the theoretical curve are then 

 determined according to scale. 



Grouping data in fairly large classes is another method of obtaining 

 satisfactory appioximations. Returns for the regional production of wheat 



