100 YEARS AGO
Mr. Marconi's Results in Day and Night Wireless Telegraphy. Reading a brief account of these results in the Times of June 14, I perceive that Signor Marconi advances in explanation of the greater distance at which night signals were received, that the day signalling is affected by diselectrification of the transmitting elevated conductor. If — as I gather — Signor Marconi is referring to his observations made at positions in the Atlantic, west of England, the waves travelling westwards, may not æther drift in the earth's orbital path be concerned in producing the effects observed? The waves advancing against the orbital æther stream in the daytime, with it at night, might be supposed to give rise to conditions analogous to those which affect the transmissibility of sound against or with a high wind. It will assist if we assume a retarded æther drift near the earth's surface and free motion above. But still, the difficulty in the explanation resides in the very great magnitude of the effects observed. I write merely by way of suggestion, and in very considerable ignorance of almost every particular involved in this explanation.
From Nature 26 June 1902.
50 YEARS AGO
In the last section of a recent paper, Dirac discusses his formulæ with the following words: “An important feature of the new theory is that it involves only the ratio e/m, not e and m separately. This is what one should expect in a purely classical theory. The existence of e should be looked upon as a quantum effect, and it should appear in a theory only after quantization, and not be a property of classical electrons”. If this point of view be accepted, some properties of electrons which have always been regarded as classical should be regarded as quantum effects; for example, the scattering of long electromagnetic radiation by free electrons. ... I am further convinced that it is futile to deal with the electron and its electromagnetic field separately, but that the fields of all mesons together with the electromagnetic field should be simultaneously considered. I have indicated a way of doing this elsewhere, and though I am far from thinking that this suggestion is right, I am still convinced that the solution must be sought in this direction.
From Nature 28 June 1952.