The methods generally used by practicing otologists for the testing of acuity of hearing are better known to the members of this Society in general than to myself, a physicist.
In the realm of physics, until recently experiments in acoustics have been performed chiefly by the use of tuning forks and of vibrating columns of air, such as organ pipes and whistles. The tuning fork is quite a dependable tool so far as constancy of pitch is concerned. As for intensity, this decreases from the maximum in logarithmic fashion, and cannot be controlled, even the attempts at maintaining a constant intensity by the use of make and break electrical contacts being in general unsatisfactory. With the organ pipes, a constant intensity may be maintained, but control of the intensity in any desired manner is not possible. With neither of these types of instruments, can all possible tones be obtained, as