Technikatörténeti szemle 10. (1978)

A MÉRÉS ÉS A MÉRTÉKEK AZ EMBER MŰVELŐDÉSÉBEN című konferencián Budapesten, 1976. április 27–30-án elhangzott előadások II. - Szabadváry F.: Tömegmegmaradás elve; mérés és számolás a kémiában

F. SZABADVÀRY* MEASURING AND CALCULATION IN CHEMISTRY Innumerable chemistry books declare—what has practically become a commonplace statement—that chemistry turned into a modern science when Lavoisier, at the end of the 18th century, introduced the use of the balance, thereby establishing the principle of conservation of matter (in modern terminology, conservation of mass) which changed this discipline into a quantitative branch of science. However, in this wide-spread view taken over from book to book, everything is erroneous, and remains erroneuous even when proving that Lomonosov introduced the use of the balance and stated the principle of conservation of matter (though only in a private letter) twenty years before Lavoisier. First of all, neither Lomonosov nor Lavoisier proved the principle of conservation of matter by utilizing the balance. They both declared this principle. Lomonosov wrote: „In Nature, everything happens in a way that when something is added to something, it is taken away to the same extent from somewhere else. So when a body takes up matter, another body loses the same amount. This law is general in Nature." He does not imply here that it was he who detected this law, but sounds rather as if he had cited something already accepted. He could not have claimed such a discovery, since his master Descartes, and even earlier Francis Bacon had already expressed similar views. Bacon wrote in 1620: ,,Nothing is truer in Nature than the two theses that nothing comes into being from nothing, and nothing turns into nothing. The absolute quantity of matter remains constant, without increase or decrease." But let us dig further back, to Aristotle for instance. He wrote :,,No matter ever disappears or comes into being, it only changes." Even earlier, around 500 B.C., Anaxagoras and Empedocle made the same statement almost word by word. It appears very probable that—as so many others—they took over this thesis from Egyptian or Babylonian sources. Consequently, the principle of conservation of matter is an ancient thesis of philosophy. We know about Lavoisier—fully acknowledging his prominence—that he was somewhat liable to wear borrowed plumes, this causing him a lot of trouble in his lifetime, and reproaches up to the present day. Yet, what he wrote in the chapter on fermentation of his text-book, does not sound in the least as the announcement of some new statement. He wrote: „Must is alcoholrf carbon oxide, since nothing comes into being neither in artificial nor in natural processes, and it can be stated as a principle that the quantity of matter is the same before and after every process, * Museum for Science and Technology, Budapest.