History of science in Belgium. 1815-2000

Brigitte Van Tiggelen 's Chemical Theories

'The instability of the theories does not deter us. We will be able to adapt them without regret when a new discovery shows us the need to do so. In the change undergone by chemical theories we shall see no sign of weakness; on the contrary, we will find in it an expression of life; an inductive science whose theories no longer change is a stagnant science. We will thus show that chemistry is a science which, by virtue of its grand aspirations and noble insights, is not inferior to other [sciences], and that, on the contrary, if one is to judge it on the basis of its contribution to natural philosophy in the past and future, it first place with her older sister, physics' (Walthère Spring,Des méthodes scientifiques et de la signification des theories dans les sciences inductives , 1877).

The 19th century was undeniably the century of triumphant chemistry, a parade of clever concepts and theories. For the first time, they seemed to fulfill the purpose of a science that seeks to decipher matter and understand its transformation mechanisms. However, a truthful reconstruction of the history of ideas is not enough to explain why chemistry was given such a special place in the culture and society of the time. The incredible development of all kinds of applications captured the imagination of contemporaries even more than the often remarkable theoretical progress. Daily life gradually changed under the influence of the chemical industry. On the border of medicine and life sciences, chemists began to decipher the riddles of life, which led to a medical revolution. The chemist, who proved his usefulness in many fields, acquired a status in society and organized a new profession. The chemists were the first scientists to encourage the use of specialized scholarly journals and organize conferences to keep abreast of the state of their fields. first France, which built on Lavoisier's legacy at the beginning of the 19th century; then England, where the socio-economic structures favored the development of a new profession and industry; finally Germany, which dominated both industrially and scientifically at the end of the century. The other countries were in the near or far periphery. They are considered recipients of new ideas that originated in the centers. For the peripheral countries, the historian's task seems to be limited to studying the diffusion, and more specifically to pointing out the obstacles or hesitations during assimilation. The pioneers of a fundamental theory are diligently sought in these lands, which eclipses other chemists who nevertheless did good work and good education. Moreover, insight into the deeper motivation of the famous predecessor is lost. Belgium, surrounded by historically important centers and especially interesting as a conduit, historians obviously pay no more attention than to countries of second or third rank. However, a detailed rewrite of the history of chemistry in Belgium does not fit within the scope of this contribution. Above all, the following pages aim to be a pleasant exploration off the beaten track, with unexpected points of view popping up here and there that can bring the history of Belgian chemists closer to the 'great' history of chemistry. historians, of course, pay no more attention than to second- or third-ranking countries. However, a detailed rewrite of the history of chemistry in Belgium does not fit within the scope of this contribution. Above all, the following pages aim to be a pleasant exploration off the beaten track, with unexpected points of view popping up here and there that can bring the history of Belgian chemists closer to the 'great' history of chemistry. historians, of course, pay no more attention than to second- or third-ranking countries. However, a detailed rewrite of the history of chemistry in Belgium does not fit within the scope of this contribution. Above all, the following pages aim to be a pleasant exploration off the beaten track, with unexpected points of view popping up here and there that can bring the history of Belgian chemists closer to the 'great' history of chemistry. The Legacy of Lavoisier and the Dualistic Theories of Matter: Jean-Baptiste Van Mons and Martin Martens At the end of the 18th century, Antoine-Laurent de Lavoisier (1743-1794) and his entourage championed a number of new ideas that completely changed the understanding of chemical phenomena. In terms of experimental method, demonstration and proof, the systematic use of the weight balance brought about a definitive turnaround. She provided proof of the new ideas. The distinction between elements and compounds, and the nomenclature based on this distinction, are still an integral part of chemical science. With the exception of the concept of 'calorique', the materialization of fire and heat, the distinction between the three states of matter of matter - solid, liquid and gas - is still taught in school. In contrast, Lavoisier's acid theory, who argued that the presence of oxygen in a compound of elements caused the acidic properties of this compound was quickly debunked. Lavoisier was still alive when his colleague Claude-Louis Berthollet (1748-1822) showed that hydrocyanic acid contained no oxygen. The discovery of chlorine and then of the other halogens definitively deprived oxygen of its privileged role among the elements. This is not so surprising when one knows that when Lavoisier coined the name 'principle oxigine' in 1772, Lavoisier implicitly relied on the principle theory of Georg Ernst Stahl (1660-1734), who explained the chemical (and physical) properties by the presence of principles in substances. To simplify the overly complex science of matter, the chemist sought to identify and isolate these principles,The affinity is nevertheless an essential part of late-18th-century chemistry that Lavoisier deliberately omitted from his discourse, despite the sincere belief that this problem occupies a central place in chemistry. Anyone who has been influenced, even from afar, by Lavoisier has somehow sought to solve the mystery of chemical affinity. The chemists in our country were no exception. Leaving aside Karel van Bochaute (1732-1793), who had no scientific followers, Jean-Baptiste Van Mons (1765-1842) was Lavoisier's most important heir. His biographers usually pay close attention to his role in the dissemination and defense of the anti-phlogiston theories; however, his other ideas were considered unworthy of a successor to Lavoisier and were therefore often underexposed.