G8 



is given as ToUows: • OH 



/ 



CHO 

 Dihydroxystearic acid as isolated from soils by 

 Schreincr and Shorcy (9) has been given the formula 



CHs. (CH07.CHOH 



I 

 COOH. (CH07.CHOH 



and melting point of 99 degrees. The compound used 



in this work had a melting point of about 121 degrees, 



and since there is no known dihydroxystearic acid 



with this melting point, evidently the product used was 



impure, and of unknown identity. 



EXPERIMENTAL WORK 



Methods 



All of the experiments on nitrification of organic 

 compounds herein reported were conducted in ordinary 

 glass tumblers, using one hundred grams of air-dried 

 soil in each tumbler. Before weighing out the soil, 

 each lot to be used was thoroughly mixed so as to 

 alTord uniform samples. Unless otherwise stated, one 

 gram of calcium carbonate, one tenth gram (or one 

 tenth of a cubic centimeter in case of liquids) of the 

 substance to be used was thoroughly mixed with the 

 one hundred gram portions of soil in the tumblers. 

 Sufficient distilled water was added to bring the soil 

 to approximately optimum water content. The tum- 

 blers were then weighed, covered and set away in a 

 dark closet in the laboratory. From time to time the 

 tumblers were reweighed, and the loss made up with 

 distilled water. 



The phenoldisulphonic acid method was used for all 

 nitrate determinations. Where large quantities of ni- 

 trates are present, the error involved in this method is 

 probably great. But the data obtained are thought to 

 be accurate enough to give reliable indications as to 

 the nitrifications of the compounds studied. The con- 

 tents of each tumbler were waslied into a quart jar 

 with 500 c.c. of a solution containing four c.c. of sat- 

 urated potassium alum, one c.c. of formaldehyde, and 

 four hundred and ninety-five c.c. of distilled water. 

 The jars were then covered and vigorously shaken at 



