; and, in order to consolidate strata of a porous texture, he
supposes water carrying minute bodies of all shapes and sizes, and
depositing them in such close contact as to produce solidity and
concretion. Now, if Dr Woodward softened stones without a proper
cause, M. de Luc, in employing the specious principle of cohesion, has
consolidated them upon no better grounds; for, the application of this
principle is as foreign to his purpose, as is that of magnetism. Bodies,
it is true, cohere when their surfaces are closely applied to each
other; But how apply this principle to consolidation?--only by supposing
all the separate bodies, of which the solid is to be composed, to be
in perfect contact in all their surfaces. But this, in other words,
is supposing the body to be solid; and, to suppose the agent, water,
capable of thus making hard bodies solid, is no other than having
recourse to the fortuitous concourse of atoms to make a world; a thought
which this author would surely hold in great contempt.

[Note 33: Lettres Physiques et Morales.]

He then illustrates this operation of nature by those of art, in
building walls which certainly become hard, and which, as our author
seems to think, become solid. But this is only an imperfect or erroneous
representation of this subject; for, mortar does not become hard upon
the principle of petrification adopted by our author. Mortar, made of
clay, instead of lime, will not acquire a stony hardness, nor ever, by
means of water, will it be more indurated than by simply drying; neither
will the most subtile powder of chalk, with water and sand, form any
solid body, or a proper mortar. The induration of mortar arises from the
solution of a stony substance, and the subsequent concretion of that
dissolved matter, operations purely chemical. Now, if this philosopher,
in his Theory of Petrifaction, means only to explain a chemical
operation upon mechanical principles, why have recourse, for an example
in this subject, to mineral bodies, the origin of which is questioned?
Why does he not rather explain, upon this principle, the known
concretion of some body, from a fluid state, or, conversely, the
known solution of some concreted body? If again he means to explain
petrifaction in the usual way, by a chemical operation, in that case,
the application of his polished surfaces, so as to cohere, cannot take
place until the dissolved body be separated from the fluid, by means of
which it is tra