178 AGRICULTUKAL EXPERIMENT STATION. [Jan. 



Neutralize exactly the 400 cubic centimeter solution with 

 sodium carbonate, covering the beaker with a watch glass dur- 

 ing the process, and make up to 500 cubic centimeters with 

 water. Add now 10 cubic centimeters of phenyl-hydrazin 

 solution,* precipitating the furfurol as furfurol hydrazon.f 

 Stir thirty minutes, preferably with an automatic stirrer, and 

 filter the solution, using suction, into glass drying tubes about 

 three-quarters of an inch in diameter and six to seven inches 

 long, drawn out at the lower end and filled with about one-half 

 inch of glass wool in preference to asbestos. Remove adher- 

 ing particles with a feather, and do not use over 100 cubic 

 centimeters of wash water. Dry the precipitate in a specially 

 constructed air bath (see cut) at 55° to 60° C. for three 

 hours. To hasten and perfect the drying a partial vacuum is 

 made by drawing dry air slowly through the tubes by aid of a 

 suction pump, the air supply being regulated by pinchcocks. 

 The air before entering the tubes is conducted throuoh 

 sulphuric acid to dry it, and through a glass tube containing 

 small pieces of marble to remove any sulphuric acid that 

 might be carried over mechanically. Cool the tubes in a 

 desiccator and weigh. Dissolve out the precipitate with hot 

 alcohol and reweigh, and consider the loss in weight as 

 furfurol hydrazon. (See cut of apparatus at end of this 

 article.) 



For the conversion of furfurol hydrazon to furfurol use the 

 following factors : — 



Furfurol = furfurol hydrazon X 0.538. 



Arabinose = furfurol h3'drazon X 1.229 + 0.0177. 



Xylose = furfurol hydrazon X 1.031—0.001. 



Pentose (average arabinose and xylose) = furfurol hydrazon X 1-13 + 0.0083. 



Pentosan = pentose X 0.88. 



FoT'imilas. 



Furfurol = C ^ H = O — C O II. 

 Phenyl-hydrazin = C « H ^ — NH — NH =. 

 Furfurol hydrazon = C < H a Q CH C " 11 = N « H. 

 Pentose =(C!^H>oOs)n. 

 Pentosans = (C s H s Q i) n. 



* Twelve grams of phenyl-hydrazin and 7.5 grams of glacial acetic acid filled 

 to 100 cubic centimeters with water and well shaken. 



t After the addition of the phenyl-h.ydrazin reagent, the solution should react 

 slightly acid. In case this is not so, add the necessary acetic acid. 



