Page:Popular Science Monthly Volume 86.djvu/621

Rh In the south wing, on the second floor, is the library, which extends up through the third floor, with galleries on each side. From the library, on the east end, extends the main lecture hall, eighty-seven by forty-three feet, and on the west end are two smaller lecture rooms. One of the principal objects of the institute will be the encouragement of research work, and a number of rooms for that purpose are on the second floor.

The main stairway ends at the second floor, in a large hall open to the roof. The side walls of this hallway are in pinkish gray stone, and the ceiling is of metal and plaster, formed and painted to represent the carved wooden ceilings of the Tudor period. Large laboratories, with lighting similar to that in the clinic, occupy the south wing on the third floor, and other rooms for research work and post-graduate instruction in the western end. In the basement are locker rooms for the students, laboratories for mechanical dentistry, the metallurgical laboratories, and laboratories and lecture rooms for first-year men, and a restaurant for students and faculty. The power house adjoins the building on the north. This contains two boilers with a capacity of 400 horse power. The engines and electric generators are capable of producing 240 kilowatts, and will furnish power for the lighting and heating, as well as for the laboratories and the chairs in the clinic.

The School of Dentistry at the university was organized in 1878, being the third dental school in America to be connected with a university. The dental school is the most cosmopolitan of the departments of the university, its students usually representing about twenty-five foreign countries and almost every state of the union. It now has a teaching staff of eighty-three professors and instructors, and six hundred and sixty-five students. The school operates a free dispensary, in which about 40,000 cases are treated annually.

When the school was first organized, it occupied for a short time a room in the old Medical Hall (now Logan Hall), and subsequently quarters in the Hare Laboratory of Chemistry at Thirty-sixth and Spruce Streets, but in 1896 it removed to a building especially constructed for it. There its growth has been remarkable, and it has long since outgrown its "new" quarters. It now enters into its fourth home. The Thomas W. Evans Dental Institute.

By concurrent action of the trustees of The Thomas W. Evans Museum and Institute Society and the University of Pennsylvania an agreement between them was executed in 1912, by the provisions of which a cooperative affiliation of the two institutions was consummated so that the resources of both have been utilized in the creation of a dental school to be carried on "as such institutions of learning are now conducted; in Philadelphia, and not inferior to any already established," as provided for in the will of the late Dr. Thomas W. Evans, an eminent scientific man and dentist who practised in Europe, but who was born in Philadelphia, and lived in a house which stood where the building bearing his name now stands, which houses the affiliated institutions, at the northwest corner of Fortieth and Spruce Streets.

no museum collection better illustrates the development of the steam engine, particularly the locomotive, than the exhibit of the U. S. National Museum. It possesses a model of a very early machine designed by Sir Isaac Newton in 1680, which was propelled by a jet of steam projected backward against the air, and a model of Denis Papin's invention of about the same time. The investigations of Savery, and Papin, and the successful experimental engines of Thomas Newcomen in 1705, with his piston and cylinder soon followed. Newcomen's ideas were improved by James Watt in 1769, who also introduced the high-pressure