THE PROGRESS OF SCIENCE 



617 



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 in- 

 stitute will be the encouragement of re- 

 search work, and a number of rooms for 

 that purpose are on the second floor. 



The main stairway ends at the sec- 

 ond floor, in a large hall open to the 

 roof. The side walls of this hallway 

 are in pinkish gray stone, and the ceil- 

 ing 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 in- 

 struction in the western end. In the 

 basement are lock'^r rooms for the stu- 

 dents, laboratories fbr mechanical den- 

 tistry, the metallurgical laboratories, 

 and laboratories and lecture rooms for 

 first -year men, and a restaurant for stu- 

 dents 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 elec- 

 tric 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 uni- 

 versity 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 stu- 

 dents 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 



VOL. LXXVI. — 42. 



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 con- 

 structed 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 pro- 



; visions 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 insti- 

 tutions 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 AY. 

 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 build- 

 ing bearing his name now stands, which 

 houses the affiliated institutions, at the 

 northwest corner of Fortieth and 

 Spruce Streets. 



LOCOMOTIVES AND STEAM EN- 

 GINES IN THE NATIONAL 

 MUSEUM 

 Probably no museum collection bet- 

 ter illustrates the development of the 

 steam engine, particularly the locomo- 

 tive, than the exhibit of the U. S. Na- 



i tional Museum. It possesses a model 



j 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 New- 

 comen in 1705, with his piston and cyl- 

 inder soon followed. Newcomen's ideas 

 were improved by James Watt in 1769, 



j who also introduced the high -pressure 



