In the years 1878 and 1879 the American physicist Alfred Marshall Mayer published his experiments with floating magnets as a didactic illustration of molecular actions and forms. A number of physicists made use of this analogy of molecular structure. For William Thomson they were a mechanical illustration of the kinetic equilibrium of groups of columnar vortices revolving in circles round their common centre of gravity . A number of modifications of Mayer's experiments were described, which gave configurations which were more (...) or less analogous to Mayer's arrangements. It was Joseph John Thomson who, in publications between 1897 and 1907, used Mayer's results to obtain a good deal of insight into the general laws which govern the configuration of the electrons in his atomic model. This article is mainly concerned with Mayer's experiments with floating magnets and their use by a number of physicists. Through his experiments Mayer made a significant, although small, contribution to the theory of atomic structure. (shrink)

Reasoning by analogy in chemical history: fallacies and guidelines. In chemistry (and natural science in general) reasoning in terms of analogy may be of great practical values as well as of theoretical significance. At the same time, however, the use of analogy is risky and the results are uncertain. In alchemy and iatrochemistry analogies between the living and the non-living nature have been carried too far. At the end of the 19th century an analogy was drawn between chemical phenomena and (...) the Darwinian theory of evolution. Another example of an overexaggerated analogy can be found in Lavoisier’s theory of acids, where oxygen was considered to be the general principle of acidity. Reasoning by analogy is mostly based on an inner conviction. It leads to provisional predictions in such cases where the required facts are not or incompletely at our disposal. (shrink)

After Jacobus Henricus van't Hoff had passed away on 1 March 1911, his pupil Charles Marinus van Deventer wrote a very personal ‘in memoriam’ in the Dutch literary periodical De Gids, pointing out that van't Hoff had merely been interested in scientific facts, not in the people discovering these facts. Van't Hoff considered the study of the history of chemistry, although by no means uncongenial, a matter of little importance. He once even said: ‘To me historical research appears to be (...) appropriate for a chemist in the decline of life, when he no longer creates professional ideas, and when the laboratory has become a burden to him’. Although van Deventer had studied physical chemistry at van't Hoff's Amsterdam laboratory and had been his assistant from 1885 until 1893, he disagreed with this verdict. Van Deventer was not only a capable physical chemist, he was also an active member of the Tachtigers, a circle of Dutch poets who around 1880 brought about a renewal in Dutch literature. He took a special interest in Greek philosophy. He did not graduate with van't Hoff, but with his colleague Jan Willem Gunning . His thesis was not based on physical-chemical, but on historical research: Schetsen uit de Geschiedenis van de Scheikunde . From 1922 to 1923 he lectured on the history of chemistry at Utrecht University. His fascinating lectures were published as Grepen uit de Historie der Chemie . This work reveals his particular interest in the development of chemical concepts. (shrink)

This paper describes the introduction of Liebig's ideas on agricultural chemistry into the Netherlands. The aversion to Liebig held by the Utrecht professor G. J. Mulder hindered the direct influence that might have been borne by Liebig's own writings; the introduction was made principally by means of Dutch translations of the text-books of the Scottish agricultural chemist J. F. W. Johnston, who generally followed Liebig's ideas.

Dutch science flourished in the late sixteenth and in the seventeenth century thanks to the immigration of cartographers, botanists, mathematicians, astronomers and the like from the Southern Netherlands after the Spanish army had captured the city of Antwerp in 1585, and thanks to the religious and the socio‐economic situation of the country. A strong impulse for practical scientific activities started from the Reformation, mainly thanks to its anti‐traditional attitude, which had an anti‐rationalistic tendency. Therefore, in the Northern Netherlands there was (...) no ‘warfare’ between science and religion and the biblical arguments leading to Galileo's condemnation were not used.Although the growth of the exact sciences and of technology in the late sixteenth and the seventeenth centuries in Protestant cirles may be partly attributed to the expansion of trade, industry, navigation and so on, this does not explain why there was also at the same time a great interest in subjects as botany and zoology, which had no immediate economic utility. There were discussions about Copernicanism and Cartesianism. So a number of astronomers and theologians rejected the earth's movement on scientific and religious grounds, but there were also those who did not reject the Copernican system on biblical grounds. In the seventeenth century there was much discussion between science and religion in the Northern Netherlands, but that discussion was not followed by censure by the Church of the State. In the Republic there was a large amount of intellectual freedom in the study of the natural sciences, thanks to practical and ideological considerations. In the eighteenth century the seventheenth century tension between science and religion changed into a physicotheological natural science. It was believed that investigations into the workings of nature should lead to a better understanding of its Creator. So Bernard Nieuwentijt in his well‐known book: The right use of‐world views for the conviction of atheists and unbelievers (1715) intended to prove the existence of God on the basis of teleological arguments. (shrink)

The Utrecht professor of physics Gerrit Moll , well-known for his defence of British science against Charles Babbage's Reflections on the Decline of Science in England , did—in co-operation with members of the Natuurkundig Gezelschap at Utrecht—important work on the reception in The Netherlands of the new electromagnetic and electrodynamic discoveries . He also carried out fundamental research into the lifting power of electromagnets, which he had seen during his visit to London in 1828. In 1830, Moll published his experiments (...) with strong electromagnets having maximum lifting powers of 38 kilograms. With the results of similar experiments performed in the United States by Joseph Henry and Philip ten Eyck in mind, Moll continued his experiments with stronger electromagnets . Furthermore; he investigated the ability of very small galvanic batteries to develop a perceptible magnetism in a great horseshoe . A practical physicist, Moll was hardly interested in theoretical explanations. In The Netherlands his experiments aroused interest in the practical applications of electro- magnetic force. In the present paper, Moll's contributions to the science of electromagnetism and electrodynamics are discussed. (shrink)

On 17 November 1820 there appeared a Dutch translation of Oersted's pamphlet concerning the discovery of the effect of an electric current on a magnetic needle suspended in the earth's magnetic field . In the Netherlands a number of physicists were immediately interested in the electromagnetic and electrodynamic discoveries made by Oersted and the French physicists. They repeated and extended the experiments, and constructed new modifications of the galvanic battery for better results. They made no fundamental discoveries in this field (...) of physics, but the fact that their work was important follows from the experiments of van Beek, which confirmed Amp`ere's theory of molecular magnetic currents. Van Beek as well as Speyert van der Eyk corresponded with Amp`ere about electromagnetic and electrodynamic phenomena. In the Utrecht Universiteitsmuseum there is an unpublished letter of Amp`ere to van Beek, which is published at the end of this article. (shrink)