Читать книгу The Fontana History of Chemistry - William Brock J. - Страница 23

It is clear that the kind of chemistry inherited from the seventeenth century was changed in at least six ways by the chemists of Lavoisier’s generation: air had to be adopted as a chemically interactive species; the elemental status of air had to be abolished and exchanged for the concept of the gaseous state; the balance had to be used to take account of gases; the weight increases of substances burned in air had to be experimentally established; a working, practical definition of elements had to be established; and a revised theory of composition had to be adopted, together with a more satisfactory and less-confusing terminology and nomenclature that reflected compositional ideas. The thrust of these revisions was accomplished by Lavoisier and has usually been referred to as the chemical revolution. Does this mean, therefore, that we have to accept that there was no mood for change in the seventeenth century comparable to the revolutionary accomplishments of astronomers, physicists, anatomists and physiologists?

Seventeenth-century chemical practice encompassed four distinctive fields of endeavour. Alchemy, though intellectually moribund, still attracted attention both as a religious exercise and because, in principle, it would have given support to the new corpuscular philosophy. Practical alchemists even at this late stage of its development could still stumble upon important empirical discoveries. In 1675, for example, Hennig Brand, while exploring the golden colour of urine, caused excitement with his discovery of phosphorus. Among medically oriented chemists, iatrochemistry had received its impetus from the writings of Paracelsus, Helmont and the exponents of the acid-alkali theory. The iatrochemists were an important group because they considered their calling worth teaching. In France, in particular, chemistry came to acquire a public following that was reflected in the production of large numbers of textbooks and instruction manuals. The iatrochemists thereby helped to establish chemistry’s respectability and ensured that it would become an important part of the medical and pharmaceutical curriculum. In effect, they began the first phase of the long chemical revolution. A third chemical constituency was that of the chemical technologists, who, in a small but significant way, continued to provide data from their observations and experiments, and who encouraged the cameralistic interest in chemistry.

Finally, there was the critical, but experimentally fruitful, work of Boyle, who did not hesitate to draw upon the work of the other three fields as evidence for the mechanical-corpuscular philosophy. In his hands chemistry became a respectable science. The ‘occult’ forms and qualities of Aristotle were replaced by geometrical arrangements and (in the hands of Newton) forces of attraction and repulsion; the secrecy of the alchemists and that of the technologists was abandoned, and an attempt was made to reform the chaotic and imprecise language of chemistry. While none of these reforms resulted in chemistry as we know it, it would be churlish to deny that chemistry changed during the seventeenth century and shared in the momentum of the general Scientific Revolution.

Nevertheless, the pragmatic element remained undefined and the subject remained the two-dimensional study of solids and liquids and ignored the gaseous state until the time of Hales. Until the role of gases was established and understood, there was a technical frontier that hindered further innovation. That was why late-eighteenth-century chemical progress has always seemed so much more impressive and why, fairly or unfairly, Lavoisier’s synthesis of constitutional ideas and experiment appears as impressive as the work of Newton in physics the century before.