MURlClDiE.— WHELK. 
129 
gives the purple dye (therefore it would apply better to 
the dog-whelk^ Buccinum lapillus, or Purpura lapillus, 
which yields a purple dye) ; thus^ embroidered with 
purple is weolc-hasn-hewen ; scarlet dye is weolc~read. 
In 1684 Purpura lapillus^ the dog-whelk, was employed 
for dyeing linen in Ireland ; and Neumann says that the 
purple-fish was also found on the coasts of Ireland, and 
that some persons made considerable profit by marking 
linen with its juices. 
The shell, which is very hard, is broken by a smart 
blow, taking care not to crush the body of the fish 
within. After picking off the broken pieces, there ap- 
pears a white vein or reservoir, lying transversely in a 
little furrow near the head. This being carefully taken 
out, and characters drawn with it, or its viscid juice 
squeezed upon linen or silk, the part immediately ac- 
quires, on being exposed to the sun, a pale yellowish- 
green, which quickly deepens into an emerald green, 
then changes to a blue, and at last to a fine purplish- 
red. If the cloth be now washed with scalding water 
and soap, and laid again in the sun, the colour changes 
to a beautiful crimson, which suffers no further altera- 
tion from sun or air, soap, alum, alkaline leys, or any 
of the substances used for assaying the permanency of 
colours. 
The juice of the purple-fish receives no colour itself, 
and communicates none to silk or linen, without expo- 
sure to the sun. It seems to be the light, and not the 
heat, of the sun, that calls forth the tincture ; for when 
the cloth is covered with thin opake bodies, which trans- 
mit heat without light, no colour is produced, while 
transparent ones give no impediment to its produc- 
tion. The juice, itself, in close glass vessels, becomes 
K 
