OF ARTS AND SCIENCES. 159 



peculiar aromatic odor. It was bright yellow in color, and slightly 

 heavier than water. It was washed with water dried over calcic chlo- 

 ride and submitted to fractional distillation. The liquid began to boil 

 a little above 100° ; but the thermometer rose rapidly, and had reached 

 160° before any considerable quantity had passed over ; between 160 

 -170° it remained stationary for a long time, and then rose again 

 rapidly to over 200°. After several distillations, about sixty per cent 

 of the oil taken distilled between 160° and 165°, the greater part of 

 which boiled steadily at 162^*. The boiling point and general charac- 

 ter of the oil at once suggested the presence of furfurol, and this was 

 readily proved by its conversion into furfuramide, furfurine, and pyro- 

 mucic acid. The behavior of the oil to alkalies, however, showed that 

 it was still by no means homogeneous. When shaken with a dilute 

 solution of potassic or sodic hydrate, a brilliant yellow color was de- 

 veloped ; and in a few moments the clear liquid became turbid with 

 the separation of a flocculent yellow precipitate, which proved to be 

 chiefly pyroxanthin. In following out the method of purification 

 which was thus suggested, I found it most convenient to separate from 

 the crude oil, only so much of the higher boiling constituents as could 

 be removed by rejecting that which passed over above ITS'^ in two 

 successive distillations. The distillate collected below 175° was then 

 gradually mixed with one-fourth its volume of a concentrated solu- 

 tion of sodic hydrate, taking care to keep the mixture cool, and 

 shaking the two well together. After standing a short time, the oil 

 was separated from the alkaline solution, washed with a little water, 

 and distilled with steam. The furfurol thus obtained was suflaciently 

 pure for all ordinary purposes, and from such a product was made all 

 the pyromucic acid which has been used in the course of the following 

 investigations. 



For its conversion into pyromucic acid, it was mixed with an equal 

 volume of a concentrated alcoholic solution of sodic hydrate, and care- 

 fully stirred until the violent reaction was over. The sodium salt was 

 then thoroughly washed with ether, dissolved in hot water, and decora- 

 posed by concentrated hydrochloric acid. For the purification of the 

 crude acid, it was dissolved in a cold dilute solution of sodic carbonate, 

 taking care that the solution should remain slightly acid. The filtered 

 solution of the sodium salt was boiled with bone-black filtered, con- 

 centrated by evaporation, and finally acidified with hydrochloric acid. 

 The acid which separated on cooling was then recrystallized from 

 boiling water, and was found on analysis to be sufficiently pure for 

 further use. 



