374 Gruenberg and Gies : Notes on " bastard " logwood 



Table V. 



The letters correspond to those in TABLE IV. 



The tinctorial sequence after the above dilution is different 



from what it was before dilution as may be seen from the following 



summary : f 



Table VI. 



Before dilution (TABLE IV). 

 After dilution (TABLE V). 



The above facts are in further harmony with the foregoing 

 conclusions regarding' cause of coloration effects and relative 

 differences. 



Dilute aqueous extracts of two samples of red logwood and 

 of one medium grade " bastard" wood all showed a similar yel- 

 low color, by transmitted light. The shades of color did not 

 differ noticeably except in degree. In stronger extracts of equal 

 concentration the first two appeared more reddish. 



Treatment with alkalies, volatile and non-volatile, turned the 

 color of the red logwood extracts to a blood-red, passing into 

 purple, whereas in the " bastard " extract the shade of yellow was 

 merely deepened, passing into the dull brown color of faded oak 

 leaves. Dilute and concentrated mineral acids turned the yellow 

 of the dilute aqueous extracts of the red wood into a color rang- 

 ing from orange to bright red. In the " bastard " extract no such 

 change was perceptible. 



These differences in the behavior of the two sets of aqueous 

 extracts toward acids and alkalies correspond to the differences be- 

 tween the reactions exhibited toward the same reagents by a 



*This color was of the same intensity as the rest, but not the same shade. See 

 footnote, page 373. 



| A similar change in sequence of tinctorial intensity after dilution was noted in 

 other extracts, also. 



