40 
BULLETIN OF THE NATURAL HISTORY SOCIETY. 
Economics. This is one of a number of Molluscs which 
furnish rich purple or crimson dyes. Indeed, it was a specie® 
of this same genus which afforded a part at least of the 
famous Tyrian purple dye. Small shells of the genera Murex 
and Purpura, containing the animals, together with the color 
gland alone from larger individuals, were pounded up together 
in mortars and mixed with five or six times their weight of 
water. To this was added twenty pounds of soda to each 
hundred pounds of the mixture and the whole was placed in 
leaden or tin dishes. It was then exposed to the sun for a few 
days, until the desired hue was obtained, when the wool was 
placed in it and left for a few hours. The wool came out 
dyed unchangeably of the color reserved for the garments of 
kings and emperors. Indeed, it was far beyond the reach of 
any but the most wealthy — so very expensive was it. Sim- 
monds tells us in his “ Commercial Products of the Sea,” that 
in the reign of Augustus, one pound of wool dyed with Tyrian 
purple sold for about £36 sterling. This was because of the 
tediousness of the process, and the small quantity of color 
obtained from each Mollusc. It is now never used on a 
commercial scale, partly on account of its expense and partly 
because cheaper substitutes have been obtained from the 
cochineal insect and later from the coal tar or aniline colors. 
In the work last mentioned we find the following, refer- 
ring to the Mollusc under consideration. “If the shell of 
Purpura lapillus is broken, there is seen on the back of the 
animal, under the skin, a slender, longitudinal, whitish vein, 
containing a yellowish liquor. When this juice is applied to 
linen, by means of a small brush, and exposed to the sun, it 
becomes green, blue and purple, and at last settles into a fine 
unchangeable crimson, Neither acids nor alkalies affect its 
color, and it may be conveniently employed in marking linen 
where an indelible ink is desired.” And as Mr. Ingersoll adds, 
“The housewives of New England, therefore, have growing 
abundantly on their sea-side rocks little living bottles of 
indelible ink which cannot be excelled by any manufactured 
product for either beauty or durability, since neither acid nor 
alkali will affect its color.” In these facts are shown an 
