Ozone and the Atmosphere. By ALBERT R. LEEDS, Ph.D. Table of percentage of ozone contained in the atmosphere at various localities in the United States. Register of ozone observations for one month at Upper Saranac Lake, N. Y., giving thermometric and barometric observations, and full record of weather. Examination of methods in ozonometry. Preparation of ozone by electrolysis of water containing sulphuric acid, with 1 engraving. Preparation by electricity, with 1 engraving. Does the electric spark decompose potassium iodide? Collection and preservation of ozone. Preparation by chemical methods. Critical examination of ozonoscopes. Potassium iodide; starch; paper classification of ozonoscopes. Examination of ozonoscopes under certain conditions. Limits of the Combustibility of Gases.--The Diffusion of Salicylate of Soda.--Singular use of Fluorescein.--New Metal. Philippium By M. MARC DELAFONTAINE.--Better Pharmaceutical Education. By RICHARD V. MATTISON, Ph. G.--An El Dorado for Apothecaries. V. MEDICINE AND HYGIENE.--The Science of Easy Chairs. The muscular conditions of fatigue, and how to obtain the greatest rest. How easy chairs should be made. Prof. Huxley on the Hand. Abstract of his inaugural lecture before the South London Workingmen's College. Paint from a Sanitary Point of View. The required abolition of absorbent surfaces in dwellings. Lead poisoning from paint not thoroughly dry. Cases described in which white lead paint in dwellings never dries, but gives off poisonous particles, which are inhaled by the inmates, causing depression, weakness headache, and loss of appetite. Zinc recommended in paint to avoid lead poisoning, and the new oxy-sulphide of Zinc described, with covering qualities equal to white lead. The Purification of Sewage. By HENRY ROBINSON, F.R.S. Paper read before the Sanitary Institute of Great Britain. Progress in purifying sewage by precipitation. The use of chemicals for precipitating, deodorizing, and disinfecting. Practical data on a large scale, with cost. Average number of gallons per head of population, etc., of the successful system now in operation at Coventry and Hertford. How the water is removed from the sludge by filter presses. Drying and removal of the sludge. Theoretical and actual values of the sludge for fertilizing. VI. AGRICULTURE, HORTICULTURE, ETC.--The Broadside Steam Digger, with 1 engraving.--Shall I Plow the Lawn?--Bee Culture. * * * * * PROGRESS OF PETROLEUM. The efforts of the great majority of the Western Pennsylvania petroleum producers to obtain relief from what they deem the oppressive acts of the Standard Oil Company and the unjust discriminations of the United Pipe Lines, and the various railroads traversing the oil regions, have attracted more than usual attention to the present condition of this industry and its possible future.