Similarly the Law Building has undergone many transformations, while the old Chemistry Building, now used by the Departments of Physiology, Materia Medica, and Economics as make-shift quarters, has lost through successive additions almost all trace of that first little laboratory which exemplified the progressive spirit of the University in her early days. The new Chemistry Building on the north side was completed in 1910 and cost with equipment about $300,000. It is four stories high, 230 feet long by 130 feet wide, and is built about two interior courts. The building contains two amphitheaters, laboratories for organic and qualitative chemistry, metallurgy, physical chemistry, and gas analysis, as well as the College of Pharmacy. Just beside it to the west rises the largest building on the Campus, the Natural Science Building, which houses the Departments of Botany, Geology, Forestry, Mineralogy, Zooelogy, and Psychology. This building, which was something of a departure in laboratory construction when it was completed in 1916, is built upon the unit system, and consists essentially of concrete piers, whose uniform spacing divides the rooms and laboratories into equal units, or multiples, with practically the total width between piers opening into windows. This is, in effect, a modern adaptation of the old Gothic principle, though it emphasizes the horizontal and lacks entirely the buttresses and pinnacles which gave the medieval church builders their inspiration. It marks, however, a new era in laboratory construction, for not only are the laboratories flooded with light, but they are carefully designed for the purpose for which they are to be used. It is also to be noted that each department is installed in a complete section of four floors, from basement to top. The building, which cost $375,000, has about 155,000 square feet of floor space and like the neighboring Chemistry Building is built about an open court. The same principle of construction has also been followed as far as practicable in the new Library Building. Other buildings on the Campus which have not been mentioned elsewhere are the Physics Laboratory, the Museum, and Tappan Hall. The Physics Laboratory was built in 1886-87. Within twenty years it proved inadequate and in 1905 an addition costing $45,000 became necessary, which contains among other features a well-equipped lecture room accommodating four hundred students. Until the completion of the larger lecture room in the Natural Science Building this was in great demand for many University lectures. Tappan Hall, a class-room building, in a portion of which the Department of Education now has its headquarters, was erected in 1894-95 and stands near the southwest corner of the Campus just at the rear of Alumni Memorial Hall.