556 STATE BOARD OF AGRICULTURE. 



A SIMIVLIFIIOI) APPAKATLIS FOK MEASURING THIO CONDUC- 

 TIVITY OF ELECTROLYTES. 



Technical Bulletin No. 2:3. 



R. 1*. IIIBBARD, RESEARCH ASSISTANT IN I'lyANT I'lIYSIOLOGY. 

 C. W. CHAPMAN^ ASSISTANT PROFESSOR OF rilYSICS. 



FOREWORD. 



This bulletin entitled "A Simplified Apparatus for Measuring the Con- 

 ductivity of Electrolytes" is mainly technical physics and discusses 

 the means of improving and making more accurate the methods of de- 

 termining the conductivity of solutions. The bearing that this has on 

 certain plant physiological investigations comes from the fact that in 

 studying the question of nutrition, in particular, of the absorption of 

 water and mineral nutrients, it is essential to have very accurate means 

 of determining the salt content of the solutions used before, during, and 

 at the close of experiments. 



When Dr. Hibbard began experiments, the known methods were found 

 to be either comparatively crude, or exceedingly complicated, but with 

 the help of Professor Chapman lie has simplified the apparatus very 

 greatly while at the same time he has improved its accuracy to an equal 

 degree. 



I feel that this bulletin will be of value to workers in similar lines 

 elsewhere as well as to phj^sicists and chemists in general who demand 

 very accurate means of determining in the electrical way the salt content 

 of solutions. 



ERNST A. BESSEY. 



