LIAS. 
changed into irregular spots, lines, and shades, which 
present nothing distinct to the view. 
190. COTTAM MARBLE, which, when cut and polish- 
ed, also exhibits the appearance of a landscape, is a 
kind of compact marl. It has its name from being found 
at Cottam, near Bristol. 
191. LIAS, or CALP 3 is a kind of limestone of bluish 
black, or greyish blue colour, and composed chiefly of lime, 
silex (76), clay, and oxide of iron (21). 
This stone, when burned, forms a cement which has 
the property of setting very strongly under water. It 
has also, of late years, been employed in a manner which 
merits particular notice, for the multiplying of copies 
of drawings and penmanship. A drawing is made on 
prepared paper with a peculiar kind of ink. A slab of 
lias, about an inch thick, is then heated ; the drawing 
is placed upon it, and both are passed through a roll- 
ing press. The paper is afterwards wetted, and washed 
from the stone ; but the ink, being of a gummy or glu- 
tinous quality, becomes in part absorbed by the stone, 
and remains. The stone is then ready for the printer. 
Previously to taking off each impression, the stone is 
wetted with a sponge ; fresh ink (which is said some- 
what to resemble printers' ink, and is put on with a 
ball similar to that used by letter-press printers) is then 
applied. This is prevented, by the water, from adhering 
to any part except to the ink that had been absorbed, 
by the stone, from the paper on which the drawing 
was originally made. Paper is then placet! on the 
stone, both are passed through a rolling press as before, 
and a perfect impression of the drawing is made upon 
the paper. 
This art has been practised in Germany with great 
success; and with the difference only of the original 
drawing being made upon the stone instead of paper. 
Many beautiful specimens of drawings, taken from slabs 
of lias, may be seen in this country. It is said that co- 
pies of military drawings and orders were, to a very 
