822 SCIENCE AND FRUIT GROWING 



Observations in the case of plots of mustard led to the con- 

 clusion that, with that plant, the advantages of an external 

 position do not extend much beyond six inches from the edge 

 of the plot, the second rows generally showing a superiority 

 over the average of the internal plants only when the distances 

 between the rows were six inches or less, but none when they 

 were nine inches. An alternation in the vigour of successive 

 rows appeared possible, for the great vigour of the outer one 

 would tend to reduce that of the second, and this relatively 

 enfeebled growth of the second row would induce extra vigour 

 in the third, and so on : but it was found that no such effect of 

 any measurable magnitude existed, for out of nine series of 

 experiments with mustard, alternation in the vigour of successive 

 rows occurred only in two of them, and, even in those cases, 

 did not extend beyond the fourth rows, being, therefore, 

 probably accidental. 





