PLATE LVI 
Fig. x.—-Red-clover plants, showing the effect of treatment with calcium sulphate. 
The plants in these test tubes show the contrast in size of root between the treated 
and untreated tubes. The treated tubes were selected from various concentrations. 
Beginning at the left, tubes x, 3, 5, 7, and 9 are untreated; tubes 2, 4, 6, 8, and 10 
are of the calcium-sulphate series. Note the decided increase in length of root of the 
plants in the treated tubes as compared with those in the untreated. 
Fig. 2.—Group A , untreated; B, 0.1 per cent of calcium sulphate added to Miami 
silt-loam soil; C, 0.02 per cent added; £>,0.05 per cent added; E t 0.1 per cent added. 
