We are willing to admit that the subject of electricity is a very difficult one for the chemist to deal with—he must necessarily say much upon it, and is equally obliged to omit abstract details which are often necessary to its explanation, and yet too prolix and bulky for an elementary chemical work. So that it requires considerable acquaintance with the subject to give a perspicuous and yet concise abstract, [p063] such as may be useful to the student. Dr. Turner has not been very successful in effecting this _desideratum_, and has unnecessarily introduced two sections, the one on electricity, the other on galvanism. He also talks of the “science of galvanism,” which is in bad taste, and erroneously asserts that the energy of the pile is proportional to the degree of chemical action which takes place; a statement by no means correct, inasmuch as the energy of De Luc’s column is directly proportional to the number of alternations, and appears entirely independent of chemical action; and again, a series of 2000 plates, arranged in the usual Voltaic apparatus, when perfectly bright and clean, and the cells filled with distilled water only, give a much more powerful shock, and cause a greater divergence of the leaves of the electrometer than when the apparatus is charged with diluted acids. Here, those very singular phenomena, which electricians distinguish by the terms _quantity_ and _intensity_, appear perfectly distinct; and between these our author does not sufficiently discriminate, but jumbles the whole under the term _activity_. In describing the chemical energies, too, of the pile, or its decomposing powers, the Doctor entirely overlooks the important and curious influence of water. He says that acids and salts are all decomposed, without exception, one of their elements appearing at one side of the battery, and the other at its opposite extremity; (_i. e._ we presume, at its positive and negative poles.) But the fact is, that, excepting where it merely acts as a source of heat, nothing is decomposable by electricity without the intervention of water; the hydrogen and oxygen of which respectively accompany the elements of the other compounds. Not an atom of potassium can be obtained unless the potassa be moistened; nor can any salt be decomposed except water be present. Sir Humphry says, it is required, to render the substance a conductor; but its operation is more recondite, and there is something mysterious and still unexplained in the uniform appearance of hydrogen and oxygen at the opposite poles, when far apart in water, and in all other cases of true polar electro-chemical decomposition. At page 86, the unfortunate protectors of ships’ bottoms are introduced—a subject about which the less is said the better;—and, as to electro-magnetism, it is merely mentioned as to its leading phenomena, in the space of three or four pages; nor is anything new suggested upon the “Theory of the Pile,” as it is