88 
Journal of Agricultural Research 
Vol. 26, No. 3 
h? aVy -f ubs01 l' Soil samples, representing different types taken during 
the soil survey in various parts of the State, were available for certain 
phases of the work. The soils were ground in a ball mill to pass a ioo- 
Fl S;^~f Side T™ °{ t elec . tr <> de vessel with calomel cell and accessories. The hydrogen enters at H, and 
rZ , asl I m § the electrode is admitted at W from a reservoir above; thus both hydrogen and water 
th e electrode through the same tube I. Water is admitted only when it is desired to wash the 
* washing d ft e ™ natlo ;tt s - . The + h y dr °l en may be used to blow out the surplus water after 
2 washing. The rate of hydrogen flow is controlled by the stopcock in the tube H. A is the reservoir for the 
' Fhrnuvh e S °J U K 10 ^ du *ctly the calomel cell B below and the electrode vessel M 
i! W^lary tube C. The stopcock K can be an ungreased ordinary glass stopcock, or a Mohr’s 
t P f t Use T ° n . a tube. N -outlet tube for spent hydrogen, which passes through wai? 
k m the bottle below. Instead of this arrangement a Bunsen valve may be used. E, wire from the hy- 
Figure f ec S°f® n the ceU * ^he Pairs of wire go to the individual switches shown m 
mgure i. O, iron rod which supports the frame holding the six electrode vessels. 
mesh sieve. As all were free from fine gravel and stones this grinding 
did not alter the texture. Besides these soils there were used ignited 
soil, acid-treated soil, leached soil, and fuller’s earth. 
