264 [Recess, 



II. 0-6735 grau gave 0-8400 grin. CO a and 0-1740 gnn. Aq. 



The following is a comparison of the theoretical and experimental 



percentages : 



Theory. , Experiment. 



C ao = 120 .... 33-89 - 34-00 



H 10 = 10 .... 2-83 2-87 



Br = 160 .... 45-19 44-79 



100-00 



I likewise prepared a quantity of the corresponding methylic ether, 

 *by boiling erythrin in wood-spirit. When an alcoholic solution of 

 this ether was treated with excess of bromine, the bibrominated 

 orsellinate of methyl was produced. It crystallized in colourless flat 

 needles, and furnished on analysis the following results : 



Dried in vacua over sulphuric acid, 



I. 0-3135 grm. substance gave 0-3463 AgBr. 



II. 0-3555 grm. gave 0-4155 CO 2 and 0-0850 Aq. 



These results correspond with the formula 

 C la H 5 Br s (C 2 H s )0 8> 



as is manifest from the following comparison : 



Theory. Experiment. 



' I. II? 



C 18 =108 .... 31-77 31-87 



2-65 



47'00 

 O 



340 100-00 



I likewise prepared some alpha-orsellic acid from the South 

 American variety of the Roccella tinctoria. On treating the ethyl- 

 compound obtained from this acid with bromine, a body was formed 

 which in properties and composition was exactly the same with the 

 bibrominated ethyl-compound obtained from erythrin by Hesse, as 

 may be seen by the following analytical details : 



I. 1*1890 grm. substance gave 1-2658 grm. AgBr. 



