GILLESPIE: HYDROGEN-ION CONCENTRATION IN SOILS 



13 



recorded as the result. When the color was intermediate between the 

 colors of two successive regulator tubes, the value of the hydrogen-ion 

 exponent was estimated to one-half or one-third of the interval. 



TABLE I 



NO. 



1 



2 



3 



4 



5 



6 



7 



8 



9 

 10 



11 



12 



13 



14 



15 

 16 

 17 



18 



19 



20 



21 



22 



SOU. 



Loam, from Maryland 



Silty loam, from Maine 



Loam, from Maine 



Sandy loam, from Virginia 



Silty loan, from Maine 



Sandy loam, from Virginia 



Silty loam, from Virginia 



Silty loam subsoil, from Maine 



Silt loam, from Maine 



Silty loam, from Virginia 



Silt loam, from Virginia 



Loam subsoil, from Maine 



Silt loam, from Maine 



Muck, from Maine 



Muck, from Maine 



Silt loam, from Maine 



Clay loam suhsoil, from Maine 



Silt loam, from Virginia 



Clay, from Montana 



Loam, from Utah 



Clay, from Montana 



Loam, from Utah 



COLORIMETRIC RESULTS 



Indicator 



t-br-ph-s-pht 

 methyl red 

 t-br-ph-^-pht 

 methyl red 

 methyl red 

 dipropyl red 

 methyl red 

 dipropyl red 

 methyl red 

 dipropyl red 

 methyl red 

 dipropyl red 

 methyl red 

 dipropyl red 

 methyl red 

 dipropyl red 

 methyl red 

 methyl red 

 dipropyl red 

 methyl red 

 dipropyl red 

 methyl red 

 dipropyl red 

 methyl red 

 br-th-s-pht 

 dipropyl red 

 br-th-s-pht 

 br-th-s-pht. . . 

 br-th-s-pht 

 br-th-s-pht 

 ph-s-pht 

 br-th-s-pht 

 ph-s-pht 

 ph-s-pht 

 ph-pht 

 ph-s-pht 

 ph-pht 

 ph-s-pht 

 ph-pht 

 ph-s-pht 

 ph-pht 



a 

 o 



ho a 

 o o 



>> © 



4.3 



4.3 



4.4 



4.6 



5.15 



5.2 



4.9 



4.9 



5.2 



5.4 



5.2 



25 



2 



4 

 3 

 6 

 6 

 2 

 3 

 5 

 6 



5.5 



5.7 



5.75 



5.75 



5.9 



5.9 



5.45 



6.05 



6.4 



6.95 



6.9 



7.0 



8.0 



7.9 



8.1 



8.1 



S.2 



8.2 



8.4 



8.5 



C3 o 

 o 4J 



4.3 



4.5 



5.2 



4.9 



5.3 



5.2 



5.3 



5.45 

 5.6 



5.25 



5.55 



5.6 



5.75 



5.9 



5.45 



6.05 



6.7 



6.95 



7.95 

 8.1 

 8.2 

 8.45 



o 



H 

 H 



SA 

 *z 



O 



m 



< 



a 

 5. 



4.4 



4.6 



5.0 



4.85 



5.15 



5.2 



5.2 



5.3 

 5.45 



5.3 



5.5 



5.6 



5.8 



5.85 



5.7 



6.25 



6.7 



7.0 



8.0 



8.2 



8.25 



8.6 



* Potential in millivolts, corrected by means of calibration curve. 



