194 Miss Homer, A new coloured fluorescent hydrocarbon 
A new coloured fluorescent hydrocarbon. By Miss Annie 
Homer, Bathurst Student of Newnham College, Cambridge. 
(Communicated by Mr H. O. Jones.) 
[Bead 11 March 1907.] 
The products obtained by the action of aluminium chloride 
on naphthalene at 100° C. have been examined. Among the 
substances isolated there is a new hydrocarbon which distils 
above 300° under 10 mm. pressure as a red viscid oil. On cooling 
the oil sets to a red, transparent, brittle solid, shewing a distinct 
greenish fluorescence. 
Analyses and molecular weight determinations of the hydro- 
carbon and its nitro derivatives shew that it has the formula 
C 2tt H 22 . There is some evidence from its mode of formation and 
reactions that it contains methyl groups ; a formula can be sug- 
gested in which it is represented as the tetramethyl derivative of 
a compound C 22 Hi 4 containing five benzene rings and related to 
naphthalene in the same way as anthracene to benzene. It is 
proposed to call the new substance tetramethylerythrene. 
The hydrocarbon is very soluble in benzene, toluene, xylene, 
carbon bisulphide, carbon tetrachloride, and petroleum ether; 
fairly soluble in alcohol and acetic acid. In all these solvents 
its fluorescence is well marked ; strong solutions are red with 
a green fluorescence, dilute solutions yellow with a blue fluo- 
rescence. 
The hydrocarbon and its solutions were examined spectro- 
scopically. It was found that the hydrocarbon itself absorbed 
all the blue, green and yellow light up to light of wave-length 
5887. General absorption was shewn by solutions stronger than 
•02 u / o , the extent of the absorption increasing as the solutions 
became more concentrated. In solutions containing from *00686 
to *00254 grs. of the substance in 100 c.c. of the solvent, two 
absorption bands were visible, the one in the blue, the other in the 
violet region of the spectrum. 
In solutions containing from *00686 to *01886 grs. of the 
hydrocarbon per cent, and also in solutions containing from *00254 
to *000846 °/ 0 only the band in the blue part of the spectrum 
was visible. In solutions weaker than *000846 °/ 0 no bands were 
visible. 
The fluorescence of the substance was well marked in solutions 
containing *000098 grs. of the hydrocarbon in 100 c.c. of the 
solvent. 
The ultra-violet spectrum of this substance has not been 
examined as yet. 
