‘Until the year 1806 Sir Humphry Davy had been remarkable for the industrious and ingenious application of those means of experiment only which had been long known to chemists. He had acquired at a very early period of his life a well-established celebrity among men of science throughout Europe by the originality and accuracy of his researches, and at the same time the fluent and impressive delivery of his lectures had obtained him the most flattering marks of approbation from the public of the metropolis. But it was in the summer of that year that, in repeating some electro-chemical experiments of very doubtful authority (the production of acid and alkali by the decomposition of water), he was led into a new train of reasoning and investigation, which enabled him to demonstrate the important laws of the connection between the electrical affections of bodies and their chemical powers. This was his first great discovery.... Our author’s next great step was the decomposition of the alkalies, which he effected the succeeding year; and this, though less interesting and important with regard to the fundamental theory of the science, was more brilliant and imposing from its capability of being exhibited in a visible, tangible form. The third striking feature which distinguishes the system advanced in the present work is the assertion of the existence of at least two empyreal principles--oxygen and the elastic fluid called the oxymuriatic acid gas (chlorine).... ‘A fourth peculiarity, which, however, is less exclusively and originally a doctrine of Sir Humphry Davy, is the theory of the simplicity of the proportions in which all bodies combine--a theory the explicit illustration and general and minute application of which the science is principally indebted to our countryman Mr. Dalton.’ How far later discoveries have advanced our knowledge can be seen in the strange words, as they now sound, which Dr. Young uses when he mentions the first researches of Davy. ‘Certain bodies which attract each other chemically, and combine when their particles have freedom of motion, when brought into contact still preserving their aggregation, exhibit what may be called electrical polarities, and by certain combinations these polarities may be highly exalted; and in this case they become subservient to chemical decompositions, and, by means of chemical arrangements, the constituent parts of bodies are separated in uniform order and in definite proportions.’ * * * * * The review then gives the account of the discovery of potassium, sodium, barium, strontium, magnesium, aluminum, glycinium, zirconium, silicium, and itrium and boron. On the subject of oxymuriatic acid gas Dr. Young says ‘we cannot help thinking his tone somewhat more decisive than the present state of the investigation altogether authorises,’ and he strongly objects to Davy’s terminology; which never was adopted by chemists.