OF ARTS AND SCIENCES. 73 



undistilled substance. The less volatile parts of the distillate were 

 easily converted by washing with alcohol and ether into white plates 

 with a blue finorescence, whicli melted at 212°, aiid were therefbro 

 anthracene. The residue left by evaporation of tlie alcoholic washings 

 consisted of dibenzyl, a bi'own viscous substance containing bromine, 

 and a small amount of a yellow oil : it was tested for phenanthrene 

 by oxidation with chromic anhydride in glacial acetic acid solution, 

 and treatment of the product, after it had been freed from chromic 

 compounds with water, and from acids by weak sodic hydrate, with 

 warm acid sodic sulphite; the solution thus formed was filtered, acid- 

 ified with hydrochloric (better nitric) acid, and allowed to stand for 

 some time, when it deposited a yellow precipitate, wliich melted at 

 198°, and was therefore phenanth-enechinone. For further confirma- 

 tion it was tested, according to Laubenheimer,* as follows : a little 

 of the substance was dissolved in about 5 cc. of glacial acetic acid, 

 a few drops of toluol, and 8-10 drops of sulphuric acid were added, 

 and the mixture allowed to stand over night. It was then poured 

 iuto water, which, shaken with ether, imparted to it a deep claret-red 

 color, exactly like that obtained from pure phenauthrenechinone under 

 the same conditions. 



In a third experiment 20 grammes of orthobrombenzylbromide were 

 treated with sodium for nearly a month in the way already described, 

 but, instead of adding water at once to the product, the organic mat- 

 ter was extracted from the sodium and sodic bromide as far as possi- 

 ble with ether and benzol, in order to avoid the reducing action of the 

 hydrogen set free by water. The residue insoluble in these solvents 

 was finally treated with water, and the small amount of organic 

 matter thus obtained added to that at first extracted. Tiie amount of 

 dibenzyl in this product was notably smaller than in those which had 

 been treated directly with water. In a weighed portion an attempt 

 was made to determine the amount of phenanthrene, by adding picric 

 acid to a strong alcoholic solution, but no crystals of the picric acid 

 compound of phenanthrene separated; the solution was therefore evap- 

 orated, and in this way a few red cx'ystals were obtained, which had 

 the form of the compound of anthracene with picric acid, and melted 

 in the crude state near 1G8° instead of at 170° ; the quantity was too 

 small to admit of purification. The formation of the anthracene com- 

 pound, which is decomposed by alcohol, apparently from an alcoholic 

 solution, can be explained by the supposition that it was not formed 



* Ber. d. ch. G., '75, p. 224. 



