e stone coffins, carefully moulded to express the
outline of the corpses within. Is the fish entire?--the nodule is of a
spindle form, broader at the head and narrower at the tail. Is it
slightly curved, in the attitude of violent death?--the nodule has also
its slight curve. Is it bent round, so that the extremities of the
creature meet?--the nodule, in conformity with the outline, is circular.
Is it disjointed and broken?--the nodule is correspondingly irregular.
In nine cases out of ten, the inclosing coffin, like that of an old
mummy, conforms to the outline of the organism which it incloses. It is
further worthy of remark, too, that a large fish forms generally a
large nodule, and a small fish a small one. Here, for instance, is a
nodule fifteen inches in length, here a nodule of only three inches, and
here a nodule of intermediate size, that measures eight inches. We find
that the large nodule contains a Cheirolepis thirteen inches in length,
the small one a Diplacanthus of but two and a half inches in length, and
the intermediate one a Cheiracanthus of seven inches. The size of the
fish evidently regulated that of the nodule. The coffin is generally as
good a fit in size as in form; and the bulk of the nodule bears almost
always a definite proportion to the amount of animal matter round which
it had formed. I was a good deal struck, a few weeks ago, in glancing
over a series of experiments conducted for a different purpose by a lady
of singular ingenuity,--Mrs. Marshall, the inventor and patentee of the
beautiful marble-looking plaster, _Intonacco_,--to find what seemed a
similar principle illustrated in the compositions of her various
cements. These are all formed of a basis of lime, mixed in certain
proportions with organic matter. The reader must be familiar with
cements of this kind long known among the people, and much used in the
repairing of broken pottery, such as a cement compounded of quicklime
made of oyster shells, mixed up with a glue made of skim-milk cheese,
and another cement made also of quicklime mixed up with the whites of
eggs. In Mrs. Marshall's cements, the organic matter is variously
compounded of both animal and vegetable substances, while the earth
generally employed is sulphate of lime; and the result is a
close-grained marble-like composition, considerably harder than the
sulphate in its original crystalline state. She had deposited, in one
set of her experiments, the calcareous earth, mi