364 SUPPLEMENT 
quantity of juice extracted, and the length of the operation of 
dyeing, the purple was so dear, that in the time of Augustus, 
one pound of wool dyed with the Tyrian purple, could not 
be bought for thirty pounds. Itis supposed that the opulence 
of the city of Tyre was much increased by the commerce of 
this precious dye. The purple decorated the magistrates of 
Rome ; but as it grew scarcer, its use was reserved, under pain 
of death, to the emperors alone. The priests, when it -was 
first known, assumed it as a colour agreeable to the divinity, 
and employed it in the public solemnities of religion. 
For a long period nothing was known respecting the two 
juices which formed the Tyrian dye, excepting what we de- 
rive from the ancients, and, indeed, we may say more espe- 
cially from Aristotle and Pliny, for no additional information 
can be said to have been communicated by other ancient 
writers ; so that, although Aristotle and Pliny had given some 
intimations of their being primitively white, and Pliny had 
mentioned one of the intermediate colours, as we have already 
seen, a green, yet the other colours which they undergo on 
exposure to the sun, were not distinctly noticed, until the 
animals themselves were discovered at the end of the last 
century, and the beginning of the present; until then, no 
adequate conceptions could be formed of the changes they 
underwent before they became purple. 
The buccinum was found in 1686, by Cole, in great plenty 
on some of the Irish shores, on the shore of Somersetshire, and 
the opposite shores of South Wales. Its juice was profitably 
employed to mark linen of a fine durable crimson. A small 
species of the buccinum was likewise found by Jussieu on the 
French coast. Cole found the juice of the buccinum, when 
taken out of the vein or reservoir, to be white and clammy ; 
and if this viscid juice be then squeezed on linen or silk, it 
immediately, on being exposed to the sun, acquires a pale 
yellowish-green hue, then changes to a blue, and lastly to a 
ee 
