Elements of Chemistry

Summary

Elements of Chemistry (Traité élémentaire de chimie, Paris, 1789) is Antoine Lavoisier's systematic textbook of the new chemistry he had built over the previous fifteen years. The library text is Robert Kerr's English translation, published at Edinburgh in 1790; Kerr, an Edinburgh surgeon, added Fahrenheit temperatures in brackets beside Lavoisier's Réaumur degrees and appended rules for converting French weights and measures, and the text describes the thirteen copperplates of apparatus drawn by Madame Lavoisier. The Preface explains that the book grew out of the reform of chemical names undertaken in 1787. Quoting the Abbé de Condillac, Lavoisier argues that a science consists of facts, ideas and words, so that one cannot improve the language of a science without improving the science. He resolves to proceed only from the known to the unknown and to draw no conclusion not grounded in experiment. He sets aside the ancient debate about four elements as metaphysical and defines elements practically, as the substances analysis has not yet been able to decompose. Part First, in seventeen chapters, sets out the doctrine. Heat is treated as a subtle fluid, caloric, whose combination with bodies makes them solid, liquid or gaseous. Chapter III describes the famous experiment in which mercury heated for twelve days in a closed vessel of air absorbs part of it, leaving an unbreathable remainder, while the red calx yields back pure air when heated more strongly. Lavoisier names the respirable part oxygen, the acid-maker, and the other azote, the lifeless. He shows that combustion, the calcination of metals and the formation of acids are combinations with oxygen, that water is composed of oxygen and hydrogen, and that the old phlogiston is unnecessary. Chapter XIII analyses vinous fermentation by weighing sugar, water and yeast against alcohol and carbonic acid, stating as an axiom that in all operations of art and nature nothing is created and the same quantity of matter exists before and after. Part II gives the Table of Simple Substances, thirty-three in all, including light and caloric, followed by tables naming the neutral salts formed by each acid with each base. Part III describes the instruments and operations of chemistry: balances, the pneumatic apparatus and gazometer, the ice calorimeter designed with Laplace, distillation, crystallization, furnaces and deflagration. The book was quickly translated and became the textbook of the chemical revolution. Five years after its publication Lavoisier was executed with the other former farmers-general of taxes.

Top Lessons

• Weigh everything

  Lavoisier's decisive tool was the balance. By weighing what goes into a reaction and what comes out, including the gases earlier chemists let escape, he showed that burning metals gain weight by absorbing part of the air and that fermentation rearranges matter without creating or destroying it. Careful accounting turned chemistry from a collection of recipes into a science of quantities.

• Words shape thought

  The Preface argues that facts, ideas and words are like three impressions of one seal. Names such as 'oil of vitriol' or 'flowers of zinc' said nothing about composition; names such as 'sulphuric acid' and 'sulphate of potash' carry the analysis within them. Lavoisier shows that a clear vocabulary is not decoration but an instrument of knowledge.

• An honest definition of an element

  Rather than speculate about ultimate atoms, Lavoisier defines an element as whatever analysis has not yet decomposed, and he admits that some of his simple substances may later prove compound. The lime and other earths on his list were later decomposed, which shows the wisdom of the provisional definition.

• Science as a common work

  Lavoisier says that frequent conversation with Berthollet, Fourcroy, Laplace and Monge had created a community of opinions in which no one could always tell his own ideas from his friends'. The new chemistry was the work of a circle, and of a household, since Madame Lavoisier drew the plates.

Verified Quotes

Medical Lens

Elements of Chemistry deliberately leaves aside respiration and animal heat, but it lays the chemical foundation for both. The analysis of air distinguishes the respirable portion (oxygen) from the part fatal to animals (azote), and Part III describes the ice calorimeter with which Lavoisier and Laplace measured the heat given off by a guinea pig and compared it with the heat of burning charcoal, an early quantitative link between respiration and combustion. Lavoisier's later experiments on human respiration with Armand Séguin (1789–1790) carried the programme further. The reformed nomenclature transformed the names of drugs and salts in pharmacy, so that the pharmacopoeias of the following decades adopted names such as sulphate of magnesia in place of the older terms. The translator, Robert Kerr, was an Edinburgh surgeon. In a passage on light Lavoisier observes that people grow less healthy in sedentary manufactures and crowded city lanes and better in open-air labour, an observation of the kind later taken up by sanitary reformers. Lavoisier was also a member of the Royal Society of Medicine and served on the 1784 royal commission that examined Mesmer's animal magnetism, though neither appears in this book.

• Part I, Chs. III–IV

  Air is separated into a part that supports respiration and combustion and a part that kills animals forced to breathe it; the names oxygen and azote are given.

• Part II, Sect. III

  Light is necessary to the health of plants and of people, who decline in sedentary manufactures and crowded houses and improve in open-air labour.

• Part II, tables of neutral salts

  Tables give the new systematic names for the salts used in pharmacy and medicine, with the old names beside them.

• Part III, Ch. III

  The calorimeter measures the caloric released in combustion and in the respiration of animals; guinea pigs are recommended as subjects.