The Author in certain parts of this treatise having been misunderstood, is anxious to state more prominently than in the first edition, that no argument illustrative of design has been founded on the supposed molecular arrangements which he has given; and that the reality of design in the phenomena of chemistry is no more affected by the truth or falsehood of his theory, than the moral of a fable is affected by the truth or falsehood of its imaginary incidents.

The phenomena of chemistry can neither be represented by figures, nor adequately described to the inexperienced by words. The consideration of chemistry, therefore, with reference to the argument of design, presents peculiar difficulties. After much reflection the author has omitted details which every treatise on the subject will furnish, and has endeavoured to convey some notion of the wonders of molecular action. As the best suited to his purpose, a sketch of his own views is given: and if the uninformed reader learn from this sketch, that the invisible operations of chemistry, are at least as wonderful as the visible operations of mechanism, the author will attain one of his objects. He will attain another object, if what has been stated, in any way contribute to the advancement of knowledge.

In this edition the introductory observations have been enlarged; a few errors have been rectified; and the arrangement of some parts altered: but with the exception of these changes, the work remains essentially the same as in the first edition.