86 DR. EDWARD SCHUNCK ON SOME 



it is combined in order to unite with alcohol and indigo- 

 blue^ for which it cannot be supposed to have any strong 

 chemical affinity? 



3. The physical properties of these compounds do not 

 seem to depend in any way on those of their constituents. 

 Nevertheless it is to be observed that those containing the 

 largest proportion of alcohol are insoluble in alkalies, 

 whilst those in which the indigo-blue preponderates are the 

 least soluble in alcohol and ether. 



4. No law or rule can be detected determining the number 

 of atoms of alcohol and acetic acid which are capable of 

 uniting with the indigo-blue. Were the series more exten- 

 sive^ it is probable that some such law might be found to 

 prevail. It may be remarked, however, that all the pro- 

 ducts insoluble in water, with one exception, contain either 

 8 or 1 o equivalents of oxygen (assuming the formula of C 

 to be doubled), as will be seen from the following tabular 

 view of their formulae : — 



^•■■■••lCsoH,,N,0,o 



^ tc,oH,3N O, 



C C,,H,,N,0, 



D C,,H,,N,0,„ 



E C,,H,,N O, 



5. Regarding the rational formulae or probable internal 

 constitution of these compounds I hardly venture to indulge 

 in any speculations. They might be considered as conju- 

 gated compounds — compounds of which organic chemistry 

 affords so many examples; and it might consequently be 

 possible to obtain from them, by decomposition, some of the 

 simpler bodies which are known to have entered into their 

 composition. 1 have, however, been unable to discover any 

 facts in favour of this view. Neither indigo-blue nor any 

 of its products of decomposition can be obtained from them 

 by any means which I have tried. In one experiment 



