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wrong, and the response to an incorrect a n swer can give the student misleading information about ernrrr. For example, in one stoichiom~trylesson, any answer that does not include the units "mdes" when entered elicits the remanse "Don't furret 'mol'units." If the numerical part of the answer is wrong as well. there is no indication of this. When ~~, the ~ t u d e n trc-enters the original answer, including the units, the response is''r&r to the balanced eq~ation."This sequence ran he very frustrating to a student. At the very least, the fact that two errors have been made (a computational error and an omission of units) should he indicated after the first incorrect entrv. There is no attemot t o exolain to students where they made thr misrnk~. After three attempts, the correct answer is given, hut no explanation or drtailed solutim accompanies it. These are serious shortcomings. To give misleading information, as in the case cited above, is worse than providing no feedhack a t all. In addition, the potential of a cornouter as an instructional aid is realired only if the student rrtponse is analy~ed and thr program then helps the student learn the material hy pointing out specific errors and illustrating correct solutions. In the Graduated Masware lesson, cstimates are allowed only in incrementsof 0.02 mL. Answers of 7.82 and 7.84 are accepted as correct: hut an answer of 7.83. in which the third digit isodd,cannot beentered. Weask our students to rstimate to the nearest Ir.01 mL, su this lesson might lend to ~mfurion. In some sections, the correct answer is given after the student has made three incorrect responses. This is good because i t prevents the student from really becoming frustrated. In other sections. a correct entrv is required before the student can proceed, regardless of the number of incorrect entries. In general the animation did not seem to add much t o the programs. The animation showing the synthesis of a polypeptide was tediously slow as were the eleetron-shifting illustrations of the mechanisms of carhonyl reactions. and the oolarimeter simulation was wry difficult to undrrstand. One d t h e hest lesson4 was thr idrntifirntion of an unknown lipld. The students ran choose from a series of tests, run the tests, and then identify the lipid. Seven different lipids were generated as unknowns. The reviewers feel this series is of marginal value. The lessons are easv to use and are generally accurate from a chemical point of view. Howewr, they do not fully utilire the capabilities of a romputer, eithcr as mt.dium for simulating chemical phenomena or as a tool that can analyze a student's response and accordingly get the student "pointed in the rieht direction." It is felt that the students w i o use these programs will he conscientious but apprehensive about taking a chemistry course and feel they will need every bit of help they can get t o eomplete the course satisfactorily. The confident, average and above student will not be challenged and the unmotivated student will not he stimulated by these lessons. ~~
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Amedeo Avogadro: A Scientific Biography Mario Morselli, Chemists and Chemistry Series. D. Reidel Publishing Co., Dordrecht, Holland. Boston, Mass., Lancaster, Engl., 1984.xi 375 pp. Plates, Figs., and tables. 15 X 22.5 cm. $59.50.
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Jerry L. Sarquis and Arlyne M. Sarquis Miami University. Oxford.OH 45056 Miami University, Middletown, OH 45042
The molecular hypothesis announced in 1811 hy Lorenzo Romano Amedeo Carlo Avogadro, Conte di Quaregna (1776-18561, is a prime example of a scientific hreakthrough that was ignored, rejected, misunderstaad, and consigned to oblivion for a long time before being recognized and adopted by the scientific world. As such, its "history" is discussed by even the most nonhistorically minded instructors of introductory chemistry courses. Yet, in this case it would be only a slight exaggeration to advise such instructors that, in the words of a Firesign Theatre album, "Everything You Know Is Wrong." And in the same vein, this thoroughly researched and thought-provoking hook might be titled "Evervthine You Alwavs Wanted To Know About r\vc~gadro.'' Ri~sedon fuurwm yeam'srudy ofthe hnoks and journals consult~dhy . 4 ~ 0 ~ a dar r 0 well as his manuscripts and other primary sources in archives and library collections, Morselli's monograph is the first in Reidel's "Chemists and Chemistry" series, which is "devoted to the examination of the history and development of chemistry from its early emergence as a separate discipline to the present day." In view of its position as a cornerstone of modern quantitative chemistry, it is not surprising that a number of myths have arisen about Avogadro's hypothesis. These legends, created by some of our greatest historians of chemistry from 1860 on and slavishly copied by textbook authors, are examined in depth by the author, who follows neither the orthodox historical approach nor the revised approaches recently favored by some historians of science. MorseUi warns us, "If, in teaching a science, historical considerations must be introduced, then figments of imagination cannot prevail over history. Accordingly, those who practice a science and those who write its history should welcome periodical re-evaluations of important seientific events, such as the molecular hypothesis. T o do otherwise would only lead to had history and to bad science." One of the most misleading myths which Morselli refutes is that Stanislao Cannizzaro convinced his fellow chemists of the crucial importance of Avogadro's hypothesis in the forqulation of correct atomic and molecular weights as a result of his presentation a t the Karlsruhe Congress in 1860. Morselli accomplishes this by a detailed examination of Cannizzaro's Faraday Lecture t o the Chemical Society, London (May 18721, in which Cannizzaro attemoted to nrovide full con-
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heen accepted a dozen years earlier. The lecture is also of interest to chemical educators since it presents Cannizzaro's philaaophy of science and of the teachine of chemistrv. Another myth dcmollshed I,? hlmtclli is the wmmon htlicf that Avogadro h ~ pruu pmed that the mulrcul~sot'theg a ~ e ~ u s c l e ments are diatomic, a conclusion due t o Cannizzaro, who did not merely "resurrect"
Avogadro's hypothesis but translated it into more modern terms. Other minor misconceptions common to textbooks that are corrected are that Avogadro was a practicing chemist (he was an ecclesiastical lawyer and theoretical physicist), Cannizzara's teacher (they never met), and a Professor a t the University of Turin when he proposed his great generalization (he taught mathematics and physics a t the Royal College of Vercelli). Amone the reasons for the neelect of Avogadra's hypothKs adduced by Morselli was his failure to he perceived as an impressive figure. In an age of IMliant experimenolmts, Avogadro was a theoretician with little new experimental evidence to report. He had few personal contacts with other scientists, never crossed the Alps from his native Piedmont, and was largely unknown in the European scientific communitv. Also. Berzelius was ing chemist of his generation he was responsible for perpetuating this confusion. Dumas, as the authoritative spokesman for the French school, had a similarly negative effect on the adoption of the hypothesis by his misguided efforts to combine Ampbe's and Avogadro's concepts. Although much of the hook is naturally devoted t o Avogadro's best known work and its reception from 1811 to the beginning of the twentieth century (three chapters, 185 pp.), his earlier electrical and electrochemical studies as well as his later eclectic works are not neglected (four chapters, 100 pp.). Avogadro's life as well as his work are evaluated within the scientific, social, and political context of his times. This scholarly endeavor, replete with 1132 notes (with some duplieation) and a 9-page bibliography, will be of interest to chemists, physicists, historians of seience, and chemical educators, especially those teaching general chemistry. George B. Kauffman California State University. Fresno Fresno. CA 93740
Chemical Demonstrations: A Handbook for T e a c h e r s of Chemistry, Volume 1 Bassam 2.Shakhashiri, The University of Wisconsin Press, Madison, Wisconsin, 1983. xxiv 343 pp. Figs. and tables. 21.5 X 28 cm. $25.00 (20% discount$20 plus $1.50 postage and handling-to instructors who order directly and enclose payment).
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In this "first in a series of volumes aimed a t providing teachers of chemistry a t all educational levels with detailed instructions and background information for using chemical demonstrations in the classroom and in public lectures," Prof. Shakhashiri and his collaborators (Glen E. Dirreen, George L. Gilbert, Frederick H. Juergens, Rodney Schreiner, Earle S. Scott, Mary EUen Testen, and Lloyd G. Williams) have provided those of us who regularly employ demonstrations in our courses with what promises to become
Volume 62
(Continued on page A321 Number 1 Januarv 1985
A31
