The corresponding–states principle – historical background

The principle of corresponding states provides correlations and predictive power that can save untold hours of labor in the laboratory.

From the present point of view, the principle – with all its far–flung applications – seems little more than fairly straightforward dimensional analysis applied to some rather basic theory. Thus it is a bit surprising to realize that such a simple, marvelous principle has had a rather bumpy history going back over 100 years, and that only in about the last 20 years has it been taken up again as a subject of serious study by chemists and physicists, although it was used extensively by engineers for a much longer time. In particular, it has now come to have an important influence on the correlation and prediction of transport properties, in addition to the much older applications to equilibrium properties.

Why has it taken so long? It would be gratifying to believe that it is because modern researchers are so much smarter than those old nineteenth–century scientists, but a little historical perspective suggests that the real reason is that now much more is known than before. In particular, more is known about transport theory and, especially, much more is known about intermolecular forces. This knowledge has provided both the insight and the quantitative details that are the main basis for Chapters 11 and 12.