Dr. Kane on the Colouring Matters of Persian Berries. 3 



abound in the New Red Sandstone series itself, as well as in 

 the lias and other rocks above j and water from the surface of 

 the earth passing through the strata must be constantly trans- 

 porting organic matter from the surface, small in quantity 

 perhaps in a limited time, but large enough for the ob- 

 served effect when supposed to be in constant action for 

 thousands of years; and this applies with equal force to the 

 Old as to the New Red series, in which, as I have said before, 

 the same effect may be observed. 

 May 23, 1843. H. James. 



II. On the Colouring Matters of the Persian Berries. By 

 Robert Kane, M.D., M.R.I. A* 



T^HESE berries, the fruit of the dyer's buckthorn, Rhamnus 

 -■- Tinctoria, are imported from the Levant and from the 

 south of France, for the use of dyers, to whom they furnish a 

 yellow colour of great brilliancy, though not so permanent 

 as some others. The appearance of the berries, as found in 

 commerce, varies considerably; some samples, and those the 

 most valuable, being larger, fuller, and of a light greenish- 

 olive colour, whilst others are smaller, as if shrivelled, and 

 dark brown in tint. The former I consider to have the ap- 

 pearance of being gathered before complete ripening, whilst 

 the latter owe their altered character to being allowed to re- 

 main longer on the stem, or to having been incautiously 

 dried. 



The colouring matter in these two kinds is essentially dif- 

 ferent. The unripe berries yield but little colour to pure 

 water, and when digested in aether give abundance of a rich 

 golden yellow substance, to which I give the name of chryso- 

 rhamnine. The dark -coloured berries contain little of the sub- 

 stance soluble in aether, but give out to boiling water an olive- 

 yellow material, to which, in its pure form, I give the name 

 of xanthorhamnine. This substance is produced, however, 

 only by the decomposition of the former : thus, if the unripe 

 berries be boiled for a few minutes in water, they, when dried, 

 yield to aether scarcely traces of chrysorhamnine^ this principle 

 being, by contact of air and hot water, changed into xantho- 

 7'hamnine. 



Omitting the details of methods of purification and of ana- 

 lysis, the properties and composition of these bodies may be 

 expressed as follows : — 



* Read before the Royal Irish Academy, Feb. 28, 1842, and now com- 

 municated by the Author. 



B2 



