260
JOURNAL OF CHEMICAL EDUCATION
FEBRUARY, 1932
rest of the day free for research. "Sandy" replied with a tired smile, "I have another lecture a t eleven.'' That lecture was never given; he was on an operating table the same afternoon and, although he lingered a broken man for nearly three years, Alexander Smith really died that day, in harness. His many friends, knowing his worth, will long cherish him in their memory. Literature Cited ( I ) Smm m~ HAI.L, "The Teaching of Chemistry and Physics in the Secondary School." Longmans. G r e b & Co., New York City, 1904, pp. 1-227. (2) SMITH. "Introduction t o General Inorganic Chemistry." The Century Co.,
(3) (4)
(5) (6)
New York City. The 1917 edition of this h w k should, if possible, he consulted in this connection, since i t represents the man a t his prime. In earlier editions he was merely "feeling his way," while in later revisions his typical humor is frequently obscured by Kendallisms. S m m . "The Training of Chemists," Science, 43, 619-29 (May. 1916). Reference (1). p. 36. Reference (1). pp. 6 M . SMITH,"An Early Physical Chemist, M. W. Lomonossov;' J. Am. Chern. Soc., 34, 109-19 (Feb., 1912).
Electron's speed and location lmowahle hut not where it is going. Where an electron is and how fast i t is moving can be measured, hut science cannot tell exactly where i t is going. Prof. E. L. Hill of the University of Minnesota recently told the meeting of the American Physical Society. Prof. Hill restated the famous "uncertai~ty principle" which has so profoundly modified the conce~tiouof the reliability. of physical science in recent vears. The . . original uncertainty principle, enunciated four years ago, led physicists to doubt if future physical events can he predicted with complete certaintv. "According t o the ideas of the new quantum mechanics, as they have been developed in the last few years," Prof. Hill explained, "it is not possible to follow in detail the motion of an electron in the manner in which astronomers can follow the motion of the planets or the cornets. Instead one can, generally speaking, - only find the chance that an electron will he found a t a given place or that i t will move with a given speed. "In 1927 Heisenberg in Germany enunciated his principle of 'indetermination' or 'inexactitude' which states, among other things, that if an electron is known t o be a t a given point then one cannot tell with what speed i t is moving. This limits one very greatly in forming an idea of the way in which electrons behave. Following a suggestion made hy the Russian physicist, Prof. J. Frenkel, I have found that the equations of wave mechanics permit of a somewhat different interpretation, according to which an electron has a definite speed when it passes through a given point, but that one cannot tell which way i t is aoina. - "The speed which it has is just the speed it would have if i t were governed by Newton's dvnamical laws, hut the inabilitv t o tell in which direction i t is movine - is a result of the fact that the electron obeys the laws of quantum mechanics instead of Newton's laws. This result somewhat lessens the structure of Heisenberg's - orincide. . . .and makes the behavior of the clcctron much easier to undrrstand. "The details of this interpretation arc not yet comdcted. and will reauire - discussion cic~cc by physicists before they can find general a . c ~ e p ~ n c e . ' ~ ~ ~ Service ~
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