328 PROCEEDINGS OF THE OHIO ACADEMY OF SCIENCE. 



a wide range of subjects, may be regarded as the general topic 

 of this review. 



It is only proper in a meeting like this that reference should 

 be made to the relations which the state of Ohio has held to the 

 progress of discovery, in virtue of work done either within her 

 borders or by her sons. We can no more than refer, among 

 others, to the extended and varied researches of Carl Barus, a 

 native of Cincinnati, the administrative and experimental work 

 of the Mendenhalls, father and son, of which I always like to 

 recall Dr. Mendenhall's ingenious improvements of the pendulum 

 for determining the acceleration of gravity, the brilliant experi- 

 ments of Millikan, a graduate of Oberlin, and much other sound 

 and careful work done in Columbus, Cincinnati. Cleveland, and 

 elsewhere. Some of the outstanding researches will receive 

 special mention, one of them in its various parts lying at the 

 very basis of our subject of radiation. Two of the most notable 

 recent researches in acoustics belong also in this category. In 

 1895 the trustees of Harvard University, finding that a recently 

 erected lecture hall could not be used for the intended purpose 

 on account of acoustic defects, asked Wallace C. Sabine, a native 

 of Ohio, and| a pupil of Dr. Mendenhall, to devise if possible, 

 some remedy. Considering that acoustic difficulties have inter- 

 fered with human speech ever since public assemblies began to 

 be held indoors, it is surprising that Sabine found practically no 

 literature on the subject. Apparently it had never come within 

 the range of experimental investigation. Without direct sug- 

 gestions or data derived from other work, Sabine entered upon 

 his path-breaking research. His patient and skillful experiments, 

 extending now over twenty years, have solved in great measure 

 the problems presented, and have made it possible to design in 

 advance a building which shall have any desired acoustic quali- 

 ties, or generally to remedy acoustic defects in already exist- 

 ing auditoriums. Especially ingenious and interesting are some 

 of his later methods, in which, having prepared a sectional model 

 of the audience-room under investigation, he produces upon its 

 stage a short, sharp sound from an electric spark, and after the 

 method devised by Toepler and lately improved bv Foley, photo- 



