Psychological Laboratory.— Since the es tablishment of the first psychological laboratory in Leipzig in 1875, by Wilhelm Wundt, where one room was devoted to apparatus and re search, the development of the psychological laboratory has been rapid. One of Wundt's first students, G. Stanley Hall, established the first psychological laboratory in America at Johns Hopkins University in 1::1, since which time many others have been started in the United States and foreign countries, including Japan. .
The requirements of the psychological laboratory have increased very rapidly with the development of the subject, until its housing and equipment has become a problem of great importance and interest. Many rooms and much equipment are now required for a detailed study of the various expressions of conscious mentality. Beside the rooms necessary in teaching psychology by means of experiments, other rooms for research are needed. Quiet and relaxation being often necessary, it is im portant so to arrange the rooms that the work of one student will in no way interfere with that of another student. The separate rooms should be provided with gas, electric lights and water. Where absolute quiet is required, pip ing of all kinds should be excluded, the heating being done by indirect radiation if necessary, and only incandescent electric lighting being used. The rooms should be wired for electrical intercommunication between those which may likely be desired to be used in suites where, as is frequently the case, the experimenter must be in one room and the esubjects in the other. They should also have wires leading to the rooms where chronometers and electrical record ing devices are located.
For the study of the sensations of light and the eye, its capacity and limitations, suites of rooms are desirable in many instances. These rooms should be capable of being either. well lighted or darkened to any desired degree. The equipment of this part of the laboratory includes models of the eye and the muscles governing its movements, sectional models; apparatus for studying color sensations, color mixing, color blindness, contrast, brightness independent of the color sensation; apparatus for studying op tical illusions, the sensitiveness of the retina at different points, the sensitiveness of the eye to changes in position, the sense of location and the imperfections of the eye; and apparatus for studying reactions and reaction times.
The sensation of sound requires isolated rooms where the noises produced may not reach other parts of the laboratory, and for certain parts of the work rooms that are sound and light proof. In this part of the laboratory the sensitiveness, range and analyzing power of the ear are studied. 'The equipment for the work in sound comprises models of the ear ; instru ments for producing sound, such as tuning forks, sirens, organ pipes and other sources of vibrations; and resonators for analyzing com plex sounds.
Other rooms are needed for studying the sense of heat and cold, pressure, pain and the locations of the various end organs. The ap paratus necessary is that required to produce the corresponding sensations. The effects of
different sensations on the respiratory organs and heart action is another subject for investi gation. Other parts of the laboratory are de voted to the senses of taste and smell. The equipment comprises the substances with which to test the various parts of the tongue, and also substances to produce different odors.
An essential feature of the psychological laboratory is a workshop where the many special forms of apparatus may be made, which are necessary to be used in the ever-changing problems which the scientific study of the con scious mind presents. Such a workshop con tains a fairly complete equipment for both wood and metal working with a plentiful supply of power for running the machines.
Among the special pieces of apparatus necessary may be mentioned the chronometer, the chronograph, electrically driven tuning forks, sources of mechanical and electrical energy and induction coils.
Aeronautical Laboratories.— The Central Establishment for Military Aeronautics at Chalais-Meudon near Paris led the way for aeronautical laboratories in 1884. A second was that of G. Eiffel, and a third that of de la Meurthe at Saint Cyr— the Aerotechnical In stitute of the University of Paris. The Lang ley Aerodynamical Laboratory was opened in 1913. Other aeronautical laboratories which have been very productive are those at Gottin gen, the English National Physical Laboratory, and the Bureau of Standards at Washington.
In these laboratories there are wind-tunnels spe cially constructed to give uniform wind streams at various velocities. In connection with these tunnels there are specially constructed balances to measure the left and drag on wing surfaces, the resistances of parts and the forces on vari ous shapes, and the i retarding forces on air planes as a whole. One very important labor atory established at the Bureau of Standards in 1917 is that for testing engines at reduced at mospheric pressures and the corresponding re duced temperatures simulating conditions for varying altitudes.
Municipal laboratories for the standard ization of supplies bought by cities, such as asphalt, fire hose, food for various municipal institutions and many other commodities are maintained by several cities. These labora tories not only test what is supplied for the city's use, acquired through the purchasing de partments, but also enable their agents to form more accurate specifications for further sup plies. Water, coal, gas and other things for public use are submitted to regular examina tions in such laboratories.
Chandler, 'The tion of Chemical Laboratories) (1893) ; Davis, 'Handbook of Chemical (1901) •, von Meyer, 'History of (translated by McGowan, 1898) •, Dodge, 'Elementary Prac tical Biology) (1894) • Jamieson, 'London Elec trical Engineering (1893) ; Minot, 'Laboratory Construction (Philadelphia Medi cal Journal 1900-01) ; Cajori, 'History of Physics> (1899) ; Sanford, 'Experimental Psy chology) (1898) • Scripture, 'The New Psychol (1897)Titchener, 'Experimental Psy chOlogy) (1901).