200 



Proceedings of the. Royal Irish Academy. 



the synthetical, unsaturated diketone-dyes recently prepared by us, may be 

 of some interest, and for this purpose we have compiled the following 

 table, which gives a summary of the shades given by these dyes, and by 

 eurcumin : — 



— 



Co.our given to Wool Mordanted with — 



Dj-e 



Chrome 



Alum Tin 



Iron 



Cinnamoy] -aeetyl-methane 1 , 



Dark yellow 



Light yellow — 



Bright red 



Cinnamoyl-benzoyl-methane 1 , 



Dark yellow 



Light yellow . — 



Reddish-brown 



Methyl Cinnamoyl-pyruvate 2 , 



Russet-brown 



Orange-yellow ,-, ° „ 

 ° J Orange-yellow 



Reddish- brown 



Cinnamoyl-pyruvic acid 2 , 



Brown 



Orange 



Orange 



Deep 

 Reddish-brown 



Methyl p. Methoxycinnanioyl- 

 pyruvate 2 . 



Saffron 



Orange-yellow 



Orange 



Olrve-brown 



p. Methoxyeinnamoyl-pyruvic 

 acid 2 , 



Chocolate- 

 brown 



Bright orange 



Bright orange 



Reddish-brown 



Methyl 34 Dimethoxycinnamoyl- 

 pyruvate, 



Chocolate- 

 brown 



Deep yellow 



Bright orange 



Dark 

 Olive-brown 



Methyl Methylene-3-4-dioxycin- 

 namoyl-pyTuvate, 



Light brown 



Yellow 



Orange-yellow 



Brownish-black 



3-4 -Dimethoxycinnamoyl-pyruvic 

 acid, 



Chocolate-red 



Orange-red Orange-brown 



Dark chocolate- 

 brown 



Curcumin, .... 



Brown 



Orange-yellow 



Orange-red 



Brownish-black 



It will be seen from the above table that the shades imparted to 

 mordanted wool by 3"4-dimethoxycinnaniovl-pyruvic acid and its methyl ester 

 are very similar to those obtained with curcumin — the dye of turmeric — and 

 this similarity in the shades may indeed be advanced as an argument 

 in support of the formula which has been assigned to curcumin. If we 

 compare the formulae of the three substances, curcumin (I), methyl 



Ryan and Dunlea (loc. cit.). 



Ryan and Algar (loc. cit.). 



