22 MR. WATSON SMITH ON ISODINAPHTHYL. 



solid mass in the receiver, after being put back into the one- 

 gallon iron still employed, and redistilled several times, at 

 length left a residue, which, on fractional distillation, 

 proved to contain some undecomposed naphthalin, this 

 passing over below 220° C. A very appreciable residue 

 however remained, which was distilled over, the tempera- 

 ture rising above 350 C. In this case, however, the solid 

 hard substance obtained had a deep yellow tint, almost 

 inclining to orange ; and on triturating in a mortar with 

 benzol (cold), the latter dissolved out a sticky resinous 

 body, which coloured it a fine deep red. After washing 

 once or twice, the crude body remaining was quite freed 

 from this sticky substance, and remained a sulphur-yellow 

 powder. This yellow colour was very much more intense 

 than in the case of the experiments on the minor scale. 

 By recrystallization from benzol and sublimation, it was 

 obtained colourless. 



A small quantity of this crude orange-yellow body, 

 treated with cold concentrated sulphuric acid, yielded a 

 a very fine purple solution, better developed on warming. 

 On heating more strongly, the colour changed to an indigo 

 tint, and then to a dull green. As this reaction is men- 

 tioned by C. Liebermann as characteristic of chrysene, I 

 venture to suggest that probably chrysene was present in 

 this yellow crude substance. 



With a benzol solution of picric acid in excess, no red 

 compound was formed with this body. It was found to be 

 much more insoluble in alcohol and shale- spirit than an- 

 thracene is ; from these solutions it separates on cooling in 

 larger or smaller rhomboidal plates, according to whether 

 the solutions are more slowly or rapidly cooled. It is almost 

 insoluble in ether, but easily soluble in oil of turpentine, 

 from which it crystallizes in beautiful lance-shaped crystals, 

 congregating in clusters. It is, like anthracene, very sol- 

 uble in carbonic disulphide, even in the cold. The tho- 



