worthless as far as understanding of modern chemistry is concerned. Such an attitude indicates a gross misunderstanding of the objective of a historical study; the purpose of a historical study is to improve our understanding of the present. For example, if we consult almost any college general chemistry textbook, we find that both Bergman's theory and Berthollet's idea of mass action are, in essence, present in the discussion of the factors which affect the extent of equilibrium-type chemical reactions. To say, as do modern textbooks, that the extent of reaction depends on the nature of the reacting substances is simply restating Bergman's statements about elective affinities. To say that the extent of chemical reaction depends on the concentration of the reacting substances is simply a refinement of Berthollet's statements on mass action. I n a sense the late Wendell M. Lather's book, "Oxidation Potentials," is the 20th century equivalent of Bergman's 18th century classic on elective affinities. The term affinity is still encountered occasionally, and its usage today seems to be more prevalent among British chemists. However, this is not t,o say that the concept of chemical affinity has fallen int,o disuse. Instead, the concept of affinity still survives in more sophisticated forms and under a variet,y of names. For example, t,he terms nucleophilic, electrophilic, dienophilic, and electron affinity are all widely used to designate specific types of combinations. The concept of chemical equilibrium developed as a byproduct of studies directed toward the understanding of chemical affinity, and today this concept serves many important utilitarian roles in both chemical science and technology. Certainly chemistry would not he the science it is today without the concept of chemical equilibrium; on the other hand, its progenitor, chemical affinity, continues to challenge the minds of chemists and physicists to new heights of understanding of t,he age-old phenomena of chemical combinations.
Literature Cited (1) PARTINGTON, J. R., "A Short History of Chemistry," Harper andBrothers, New York, 1960, p. 322. A,, "A Hundred Years oi Chemistry," The Mac(2) FINDLAY, millan Ca., New York, 1937, p. 110. (3) WALDEN, P. (translated by R. Oesper), J. CAEM.EDUC.,31,
-77. (19.64) - - -,. \
(4) GOATEE,G. E., "Organometallic Compounds," 2nd ed., Methuen and Co., Ltd., London, 1960, p. 346. J. W., r'Chemical Statics and Dynamics," Long(5) MELLOR, . mans, Green, & Co., NewYork, 1 9 0 4 , ~177. (6) BERTAOLLET, C. L. (translated by M. Farrell), "Researches into the Laws of Chemical .&nity," Philip H. Nicklin and Co., Baltimore, 1809, p. 1. (7) BERTAOLLET, C. L. (translated by B. Lambert), "Essay an Chemicd Statics," J. Mawman, London, 1804. J. W., op. eil., p. 178. (8) MELLOR, (9) MEYER,L. (translated by P. P. Bedson and W. C. Williams), "Modern Theories of Chemistry," 5th ed., Longmans, Green. & Co.. New York. 1888. D. 452. ~
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(11) PARTINGTON, J. R., Op. d., p. 323. J. W., op. tit.,p. 180. (12) MELLOR, F. L., Chymia,vol. 8 (in press). (13) HOLMES, J. W., op. cit., p. 182. (14) MELLOR, J. W... OD. 115) MELLOR. . eit.., n. - 183. (16) B E R T H o L ~ T , C. L., "Resertrches into the Laws of Chemical Affinity," Philip H. Nicklin and Co., Baltimore, 1809, p. 5. (17) MEYER,L., op. tit., p. 458. (18) GUGGENAEIM. E. A,. J. CHEM.EDUC.. ~ ,33.54411956) . , . (19) METER,L., op.eit., p. 423. (20) MOORE,F. G., "A History of Chemistry," 3rd ed., McGrawHillBook Co., New York, 1939, p. 372. 0. (translated by G. E. Gibson), "Thermochem(21) SACKUR, istrv and Thermodvnsmics." The Macmillan Co.. Loidon, 1917, p. 317. " (22) YAN'T HOW, J. H. (translated by T. Evan), "Studies in Chemical Dynamics," Chemical Publishing Co., Easton, Pa., 1896, p. 251. (23) VAN'T HOFF,J.H., op. Cit.,p. 148. (24) ~ A N ' THOFF,J.H., op. cit., p. 123. (25) LEWIS, G. N. AND RANDALL,M., "Thermodynamics," McGraw-Hill Book Co., New York, 1923, p. 584. (26) L ~ w r sG. , N., Proe. Amer. A d . A d s . Sci., 43,260,261, 284 (1907).
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Evaluation of Programed Instruction Programed instruction during the recitation period of the General Chemistry course was found to be beneficial to the average and below average student in an experiment which was conducted this year a-t Fairleigh Dickinson University. The 46 students in the experimental group were matched with students in the eame lecture group of the General Chemistry class according to such criteria as I. Q . and schievements in the previous year in English, mathematics, and physics. The experimental group reviewed the m a t e d that had been covered in the lectures with the help of a program; tho control group reviewed the same material in question and answer periode conducted by an instructor both orally and through blackboard written work. All students t,ook the same quizzes and the same final examination. The above average students in both groups performed on comparable levels. Among the average and below average students there were twice as many C grades and half as many D grades in the experimental group as in the control group. Only one student in the programmed group failed the oourse, compared to five in the control group. Details of the experiment and a more complete analysis of the results will be supplied interested readers upon request. LUCIANA SACERDOTE FAIRLEIGE DICEINSON UNIYERSITY TEANECK, NEWJERSEY
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Journal of Chemical Education
