Bearing of Recent Experiments on the Special and General Theories of Relativity

IN a recent communication Dr. L. Essen 1 concluded that special relativity cannot be applied to a rotating system. Jennison 2 and Synge 3 have previously treated the problem considered by Essen and have shown it to be consistent with special relativity. As the application of special relativity in this context is of considerable importance and in order to clarify its correct application the following points should be noted.