VOL.7, No. 6
CHEMICAL DIGEST
1411
equation, as de Broglie pointed out, involves another velocity u,which may be denoted by cP/o and is greater than the velocity of light. It may be thought of as a phase velocity, of which o may he shown to he the group velocity. In the case of a mass m, moving with velocity 8, if we state
hu = mcs cZ = w zr = Xv
and multiply the left sides together, and the right sides, and equate, we have after canceling A = hlmv. This is the precise relation which Davisson and Germer, and G. P. Thomson, have shown to hold for an electron. Thus the frequencies of waves seem to be achieving a remarkably fundamental =Me, comparable with that of energy. Waves of what? The key to the central tower of physics has yet to he found. No less obscure is the connection between the two different types of electric charge and their attendant waves. The linkage between energy and time, which resembles that between and q in Dirac's equations, also suggests a close relationship between energy and frequency.
Historical Apparatus of Rayleigh, Discoverer of Argon, Threatened by Fire. Sincere regret will be felt throughout the world of science a t the destruction by fire of a large part of Lord Rayleigh's laboratory a t Terling Place. Chelmsford. Essex, on March 7th. After taking his degree a t Cambridge in 1865, the late Lord Rayleigh found great difficulty in getting opportunities for experimental mearch or instruction in laboratory work. Three years later he started experiments on his own account at Terlhg Place. and from there produced a number of papers which a t once secured for him a position as a leader in physical science. When he resigned from the chair of experimental physics a t Cambridge in 1884, he continued his researches in his private laboratory, and it was there that he carried out the precise determinations of the density of nitrogen which led to the discovery of argon. The simplicity of the apparatus used hy the late Lord Rayleigh is well known, and most visitors to the laboratory were astonished that results of prime significance could be obtained with such modest equipment. We are glad to know that most of his historic apparatus has been saved as well as all of his books and papers. a stall loft-has The upper story of the laboratory a t Terling Place-riginally been burnt out; it was here that the main work on argon was done. Among the pieces of historic apparatus which have been destroyed are the original Rayleigh refractometer and the manometer used for adjusting the pressures of gases to an accurate standard in the weighings of nitrogen, hydrogen, and oxygen. Most of the present Lord Rayleigh's chief working instruments have also been destroyed and much preparatory work for experiments in progress is gone. The apparatus thus lost includes several valuable spectrographs, quartz apparatus, and lenses for investigating the optical propertierr of mercury vapor, air pumps, equipment for measuring the light of the night sky by photoelectric cells, and other instruments used in recent or current researches. It is distressing to have to record a disaster of this kind, and we ask Lord Rayleigh t o z c e p t the sincere sympathy of scientific workers everywhere a t the losses he has suffered and the consequent interference with his research work.-Nature (London)
