Poetry realized in nature

ROM HARRE, Great scientific experiments, Oxford, Phaidon Press, 1981, 8vo, pp. 224, illus., £8.95. In little more than 200 pages Dr. Harre manages to describe the reasoning behind twenty experiments, the apparatus involved, and the results. They cover a wide range of sciences distributed between Aristotle's biology and quantum mechanics. The amount of information included is remarkable. For example, he has been able, in a few pages, to outline the essentials of wave theory and the four quantum numbers used to express the behaviour of electrons. All this as a preliminary to the description of the method used by Otto Stern to demonstrate diffraction among atoms in a beam of helium. The experiments were selected by certain rather rigid criteria. Many of them are experiments that have been misinterpreted. Most were influential at the time they were done, rather than achieving fame later by hindsight. Third, the experiments chosen were elegant and often simple. Fourth, some series of experiments are described, such as Michael Faraday's demonstration of the similarity of all the various kinds of electricity. Harre is anxious to show that no experiment stands alone. What is an experiment? The author discusses the question interestingly in the introduction to his book but comes to no very precise answer. He explains that experiments should have certain fixed parameters and then proceed to use independent variables to produce dependent ones. He notes it is not possible where human actions are concerned to separate variables and parameters. It is not surprising, therefore, that the only medical experiment among the twenty he describes is Pasteur's preparation of artificial vaccines. One should surely not conclude that medicine does not use experiment. The book certainly contains materials for interesting discussion of the nature of experiment. It will be useful not only for school work but for anyone who wishes for a new insight into the history of science and the value of scientific method. J. Z. Young Wellcome Institute