296 Royal Society. 



However, it cannot be doubted that though the colour of purple 

 stuffs was primitively violet, the requirements of taste and of fashion 

 led to the variation of its shades. Thus some stuffs were dyed 

 twice, to give them a richer and more vivid colour — the so-called 

 'purpurea dibapha.' The mixture of species also contributed to 

 modify the hues. 



Murex trunculus gives an almost blue shade. The fishermen of 

 Port Mahon told me that it always yielded that colour, and especially 

 that it would give a fixed and permanent colour. On the contrary, 

 Purpura hcemastoma (which they call 'cor de fel') was known to 

 them as staining their linen very permanently and ineffaceably. 



It ought also to be recollected that when mineral colours replaced 

 the animal matter of mollusks, the hue varied ; and though the term 

 1 purple' might be retained, it was easy to pass by degrees to the 

 deep red which rises in the mind when we recollect the purple worn 

 by cardinals. 



Perhaps also the manipulations to which the molluscan dye-stuff 

 may have been subjected by the dyers, of the nature of which we know 

 nothing, approximated the purple to the red, which Pliny compares 

 to that of coagulated blood. 



But it remains none the less demonstrated, both by the passages 

 from ancient authors and by experiment, that the primitive and 

 natural colour of the purple was formerly, as now, violet. 



Hence it would appear to be requisite for a painter to consider 

 the epoch when the personages who are represented clothed in purple 

 drapery lived, for the hue varied with the age. The properties of 

 the purple dye-stuff also render intelligible one ground of the esteem 

 in which the colour was held ; for, developed by the influence of 

 light, it could not fade, like the red of cochineal for example, but 

 must always have remained beautiful, even in the luminous and 

 dazzling atmosphere of Italy and the East. 



It would be difficult, with the scanty materials we possess, to 

 determine exactly the species employed by the ancients. Without 

 Fig. 1. Fig. 2. 



Fig. 1. Animal with Purpura lapillus, with the pallial cavity laid open. 



1. Genital orifice. 3. Anal gland. 5. Branchiae. 



2. Anus. 4. Purpurogenic organ. 6. Organ of Bojanus. 

 Fig. 2. The animal simply removed from its shell. 



1. Branchiae. 2. Purpurogenic organ. 3. Anal gland. 



