The importance of electrolysis in metallurgical and analytical chemistry has already been noticed. So rapid has been the progress along these lines that the terms metallurgical chemistry and electro-chemistry are in some respects almost synonymous. Electricity has also been employed in many of the chemical arts; _e. g._, in the promotion of crystallization and purification of organic solutions as practiced in the sugar industry. [Illustration: DRIVING A NAIL WITH A HAMMER MADE OF FROZEN MERCURY.] Though belonging rather to analytical than to electro-chemistry, one may here mention the wonders of that discovery which belongs to the close of the nineteenth century, and which is known as “liquid air.” Until 1877 air—oxygen and nitrogen—was regarded as a permanent gas. Oxygen liquefies at 300° below zero and nitrogen at 320°. When air is cooled to those degrees it assumes a misty form and falls like raindrops to the bottom of the vessel. It then gives off vapor, like boiling water. If poured out on a conductor, as iron or ice, it assumes the gaseous state so rapidly as to amount to an explosion. The many experiments with it are simply wonderful, and the practical claims for it are without end. Already it runs an engine and motor vehicles. It is claimed that it will complete the problem of aerial navigation; that it is the coming power in gunnery and blasting; that it affords the ideal sanitation; that in surgery it offers the most perfect chemical cauterization. CONCLUSION. There is no branch of science that holds such an intimate relation to the progress and welfare of man as chemistry. First of all, it is chiefly instrumental in providing him with food and clothing, as has been shown in the paragraph on agricultural chemistry. In the second place it has extended his domain over matter and, in connection with physics, has established the identity of the composition of the universe with that of the earth. The universe has thus been shown to be of a single origin and of uniform properties. By understanding the constitution of matter, with which he is surrounded, man is able to utilize to the best advantage the material at his disposal. Thus invention is promoted and the application of chemical knowledge in the arts extended. THE CENTURY’S MUSIC AND DRAMA BY RITER FITZGERALD, A.M., _Dramatic Critic “City Item,” Philadelphia_. I. MUSIC.