or Yellow Gum-resin of New Holland. 441 



distilled with a mixture of carbonate of soda and water, but 

 its quantity is so small that I was unable to examine it more 

 closely. The resin is insoluble in water, but dissolves readily 

 both in alcohol and in aether, especially in the former. Its 

 solution in alcohol has a brownish yellow colour ; the addi- 

 tion of water precipitates it as a dark yellow mass, but it does 

 not crystallize out of its alcoholic solution when left to spon- 

 taneous evaporation, but remains as a varnish. When di- 

 gested with strong alkaline lyes, it readily dissolves and forms 

 a brownish red solution; and when the alkali is neutralized with 

 muriatic acid, the resin is precipitated considerably altered 

 as a dark brownish brittle mass. On concentrating the solu- 

 tion out of which the resin has been precipitated, and allowing 

 it to cool, a quantity of impure reddish crystals resembling 

 benzoic acid are gradually deposited. It requires repeated 

 and long-continued digestions with the strongest alkaline lyes 

 to remove the whole of this crystalline acid from the resin, 

 which retains it with very great tenacity. The quantity of the 

 acid is by no means great. It is not easily purified, as its 

 crystals are apt to retain a trace of a reddish colouring matter, 

 from which it is very difficult to free them. The easiest way 

 of getting rid of it, is by dissolving the impure crystals in a 

 small quantity of alcohol and then adding water; the greater 

 portion of the colouring matter is retained in solution, while 

 the crystals are precipitated tolerably white. When purified 

 by repeated crystallizations, they become quite colourless. In 

 appearance, taste, and smell they closely resemble benzoic acid. 

 When dried at 212° F. and subjected to analysis, — 



I. 0-2284 grm. of substance gave 0*6005 CO a and 0413 

 HO. 



II. 0-2955 grm. of substance prepared on a different occa- 

 sion gave 0*790 C0 2 and 0-1505 HO. 



100-00 100-00 100-00 100-00 



It is evident from these analyses that the crystalline acid con- 

 tains nearly the same amount of carbon and hydrogen as cinna- 

 mic acid, with some deficiency however in the carbon. I was 

 led therefore to suspect that it consisted essentially of cinnamic 

 acid, with probably a smalKadmixture of benzoic acid, a sus- 

 picion which subsequent experiments tended fully to confirm ; 

 for on heating a quantity of the crystals with some peroxide 



Phil. Mag. S. 3. Vol. 28. No. 1 89. June 1 846. 2 H 



