266 PROCEEDINGS OP THE AMERICAN ACADEMY. 



negative radicals bul containing no nitro groups; for, if colors of the 

 Bame class could be obtained from these, it would prove that the addition 

 of the alkaline Bubstance t <><>k place on the benzol ring and not on the 

 nitro group. We were encouraged to undertake these experiments by 

 the Btriking resemblance in properties* between our colored products 

 ami the green bodies made by Aatre f from the action of sodic alcoholati - 



on qui le. In the quinoms, however, the formation of hemiacetalsj is 



possible, and it may be that the green bodies belonged to tliis class : w 6 

 accordingly used for our new experiments Bubstances in which the forma- 

 tion of hemiacetals could not occur, such as trimesic triethylester, which 

 is especially lit for these experiments, since it has a still Btronger re- 

 semblance to trinitrobenzol than quinone has, because it contain-, three 

 negative radicals symmetrically disposed. We have not Bucceeded in 

 obtaining any colored or other addition-products from this Bubstance, or 

 from the free trimesic acid, although the attempts have been repeated 

 often and under varying conditions. Nor did we have better sua 

 with other bodies free from nitro groups, such as phloroglucine, or n 

 cine; pyrocatechine.it is true, gave a temporary coloration with Bodic 

 methylate, but we think this reaction does not belong to the series under 

 discussion. These experiments, as they have given negative results, 

 throw no light on the constitution of our colored compounds. 



It has been shown earlier in this paper that the only theory as yet 

 proposed for these colored compounds (that of Victor Meyer) is inadmiss- 

 ible, because they are addition-, not Bubstitution-products. The facts 

 now at our disposal are not sufficient to furnish an absolute proof of the 

 structure of these compounds, but it is possible to show that certain 

 constitutional formulas explain these facts better than others, and it seems 

 to us that the work has arrived at a point where such a discussion of the 

 possible formulas will be useful. In this discussion the following proper- 

 ties must be considered, as they seem to be characteristic of all the 

 members of this group. (1) The very marked color. (2) The ease 

 with which they are decomposed even by dilute acids, giving the aromatic 

 constituent unaltered. (3) Their behavior with alcohols, which we 

 describe here in some detail, because the principal observations are new. 

 When the methyl compound CV.II ,i N< V .i ( )( 1 1 \a< X 1 1 | is allowed to 

 stand lor some time with benzyl alcohol, both the methyls are replaced 

 by benzyls, and the compound CV,II.j(N(),.) ; OC;II 7 Na( K' 7 II 7 is formed. 



* These Proceeding. XXXIII 17.".. 

 t Oomptea Rendus, ('XXI. 580 (is 1 .);,). 

 J These Proceedings, XXX. 411, 



