It would be interesting to know the comments of the persons named in this note as to the cause of the dirt and confusion which reigned in the laboratory. Davy was perfectly reckless with apparatus; with him to think was to act, and he frequently had half a dozen experiments going on simultaneously, upon disconnected parts of the same inquiry. Anyone who has had the opportunity of seeing his laboratory notes, or of glancing over the rough drafts of his memoirs, which have been preserved by the pious care of Faraday, will appreciate the significance of the remarks upon his writing materials. His usual method of erasure was by dipping his finger in the ink-pot; and, if we may be pardoned the use of the colloquialism, he was simply “Death on pens!” CHAPTER VII. CHLORINE. The rivalry between the French and English chemists continued, but it took a new departure. Gay Lussac and Thenard had stolen a march on Davy by their discovery of a chemical method of making the metals of the alkalis, whereby they were able to use these metals as chemical reagents to greater advantage; but the tables were quickly turned. On July 12th, 1810, Davy read to the Royal Society his memorable paper “On the oxymuriatic Acid, its Nature and Combinations; and on the Elements of the muriatic Acid; with some Experiments on Sulphur and Phosphorus, made in the Laboratory of the Royal Institution.” This paper, in which he first demonstrates the nature of chlorine, is very short--only some twenty-six quarto pages--but it is unquestionably one of the most brilliant, as it is one of the most forcible of his productions. Davy is here seen at his best. He is bold and yet wary, and as dexterous as trenchant; so confident is he in the strength of his position that he casts aside every argument that might tell in his favour, unless it is based on the most unimpeachable evidence. It is difficult to know what to admire most--the clearness of perception, the precision of the statement, the strictness of the logic, the aptness of the illustration, or the argumentative skill with which the whole is marshalled and presented. As a piece of induction, the memoir is a model of its kind, and as an exercise in “the scientific use of the imagination” it has few equals. Most scientific papers will stand a considerable amount of winnowing, and there is no assay-master more scrupulously strict than Time. “The more a science advances, the more it becomes concentrated in little books,” says Leibnitz; but the most fastidious of critics might read and re-read this work without wishing to omit or amend a sentence.