It was the time of the creation of present-day chemistry and geology, and their synthesis gave birth to geochemistry. At the same time, applied scientific disciplines were being created on the basis of the new scientific ideas of matter and our planet – they were understood as technology then. This is extremely important too, because both in ‘technology’ in the broader sense and in pure knowledge we come across thoughts about geochemical problems – the deepening of these problems. The history of chemical elements in the Earth’s crust, their role in different chemical processes, and particularly in the phenomena of life – both in living nature and in daily human life – has permeated scientific thought since the end of the eighteenth, and beginning of the nineteenth century; it has had various manifestations occurring everywhere.
I shall mention three of the most outstanding predecessors of modern geochemistry of the last century. These are the Englishman Humphrey Davy (1778–1829), the Prussian German J. C. Reil (1759–1813), and A. von Humboldt (1769–1859). The brilliant key work of A. von Humboldt, a Prussian by origin, was published outside Prussia. As for himself, in the first decade of the nineteenth century he was completely under the influence of the intellectual atmosphere of Paris.
Humphrey Davy was a brilliant experimenter, physicist, and chemist who covered all the science of his time; he was a thinker possessing a deep poetic understanding of nature. He always connected science with life and was one of the most brilliant figures of the first half of the nineteenth century, which was so rich in talented people. Davy made a tremendous impact upon the science of his time by his lectures, numerous articles and books, and by brilliant experiments. In his works we find a lot of data about the history of chemical elements in the Earth’s crust. In this field he developed the ways discovered by Rouelle and Lomonosov on a new scale. His works were a prototype of all the later treatises of chemistry in which the account of the properties of chemical elements is always connected with their geochemistry. In the later works of Dumas, Bercelius, Liebig, Mendeleyev, and other, no less talented scientists, we always find speculations or brilliant generalizations concerning geochemical problems. After Davy, during the entire nineteenth century, geochemical problems were included into inorganic chemistry courses; they were studied while discussing particular chemical elements.
The fate of Reil was quite different. One of the most outstanding doctors of his day, absolutely committed to helping the suffering, he did not spare himself and died on duty. Reil died in the very midst of his scientific searches. Being a doctor, an anatomist, a psychiatrist, and a physiologist, he was not interested in geochemical problems directly. But he was a man of broad philosophical thinking, a naturalist, like all the genuine doctors of his day. As a philosopher he shared the trends of natural philosophy, and apparently he was close to Schelling, but his thought was independent. His contribution to the history of geochemistry is connected with the study of the chemistry of organisms. He was the first in the era of the new chemistry to suggest the importance of the chemistry of organisms, and in this respect he was far ahead of his time.
The roots of Reil’s aspirations and ideas go far back into the medical tradition. Beginning with the petrochemists of the seventeenth and eighteenth centuries, maybe even with Paracelsus (Bombast von Hohenheim, 1493–1541), the importance of chemistry in medical systems and in the understanding of healing the sick had never left the intellectual horizon of doctors. Generations of doctor-chemists follow one another incessantly for centuries. Reil considered the thorough, quantitative chemical study of organisms necessary, and he searched there for the answer to the manifestations of life. He was an innovator whose work was stopped by death at the very beginning. It is difficult to say what Reil’s contribution could have been, had his life been longer.
This was also the way of thinking of one of the most striking people of the first half of the nineteenth century: Alexander von Humboldt. In his early works, especially in “Flora Fribergensis Specimen” (1793), written before he plunged into South American nature, A. von Humboldt had come very close to many of the present-day problems of geochemistry. These studies of the young Humboldt were interrupted by his long journey, the processing of its results and the creation of the striking synthesis presented in his Cosmos. As an old man, in the fifth volume of Cosmos, he returned to one of the geochemical problems: the influence of life on its surroundings. But death stopped this work in the middle of a word.
In the paper of 1793 mentioned above, there was a brilliant effort to describe living organisms from the point of view of their chemical elements; being a mineralogist and a geologist, Humboldt never ceased seeking for their origins in the inert matter surrounding the plants. Decades passed until the problem was posed again as clearly as it had been by Humboldt. His way of putting forward the problem of the geographical spreading of organisms goes far beyond the limits of the studies of his followers; and deeper than the new branches of geography that appeared under its influence; it approaches the geochemical concepts of our days. He considered living matter to be an unbreakable and regular part of the planet’s surface, inseparable from its chemical environment.
During the entire nineteenth century, the field of contemporary geochemistry was being prepared. Step by step, the picture of the unity of the chemical composition of the Universe was becoming clear. This unity was first put on an experimental basis after the idea of the cosmic origin of meteorites penetrated the scientific mind. That idea was born in the first quarter of the nineteenth century, thanks largely to the continuous (1794–1826) scientific work of E. F. Chladni (1756–1827), an original scientist who, like Humboldt, stood apart from German university science. Chladni, who was not a chemist, followed his own path in life and was an innovator in science. The chemical composition of meteorites being identical to that of terrestrial bodies was first stated by E. C. Howard (1802), and at the same time J. L. de Bournon found out how they differ mineralogically. Both statements soon entered the scientific mind, but conclusions were drawn much later.
The notion that the chemical elements of living organisms were identical to those of inert matter was slowly acknowledged by science. Until the 1740s, it was not considered scientifically proven and was checked by special experiments. By the middle of the nineteenth century, following the methods brilliantly worked out by H. Davy, scientists had discovered the principal features of plant nutrition, which were then immediately taken up on a planetary scale (i.e., studied not only in their biological, but also in their geochemical aspects). This tradition has continued since the time of Lavoisier.
J. B. Dumas (1800–1884), J. Boussingault (1802–1887), K. Sprengel (1787–1859), J. von Liebig (1803–1873) and many researchers who followed them, or their contemporaries whose work was partly independent, stated the geochemical significance of green life. As we shall see, this life refers to the main part of the living matter of the biosphere. Dumas, Boussingault, and Liebig discovered the importance of green life in the gas exchange of the planet, and apparently it was Boussingault who had the deepest understanding of it, for he understood the geochemical aspect of the phenomenon best of all. He came across it outside the laboratories – in nature – during his long stay in the tropics and his studies of volcanic phenomena and minerals. In this field he was one of the shrewdest thinkers of the nineteenth century, and up till now we find in his works new material that has not been covered by scientific thought yet. Sprengel and Liebig furthermore discovered the real significance of the ashy elements. The theoretical constructions of Liebig influenced our understanding of these phenomena and completely reversed the explanation of the century-long characteristic of human culture – the importance of fertilizers for the productivity of soils. They also showed the geochemical role of green plants by using the