40 MOLLUSCA. 
fluence in brightening the colour. My experiments 
were performed in winter, and I will not affirm that 
the intensity of a summer’s sun would not in some 
degree have modified the result. ‘There appears 
to me one objection to this material ever having 
been used to dye large surfaces of uniform colour ; 
for from the admixture of mucus with the colouring 
matter, when any quantity of the latter is collected, 
the hue is found to imbue the cloth in a mottled 
or blotched manner, some parts being much darker 
than others. What method the ancients had of 
avoiding this appearance [ do not know. 
I have seen it repeatedly stated that the slimy 
liquor remaining in the shell of the common snail, 
when the animal is crushed, is an admirable ce- 
ment for glass or china, resisting both heat and. 
moisture. I have tried it both simple, and mixed, 
as sometimes directed, with quick-lime in powder, 
but am compelled to confess, that I found it ut- 
terly worthless, the adhesion being in every case 
no greater than if I had used spittle for the 
purpose. 
Let us now see what rank the Mollusca can 
assume among those creatures which inflict di- 
rect injury upon man. ‘The ravages committed by 
various species of snails and slugs are often an- 
noying, and sometimes serious. There are pro- 
bably few of my gentle readers who have a garden 
at their disposal, who have not been disappointed 
of their crops of spring flowers by the nightly 
depredations of these pests. The border has been 
well dug and smoothed, the seed has been carefully 
sown, and the spot has been eagerly watched from 
day to day; but no sooner have the tender seed- 
leaves appeared above ground in a slender green 
