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In 1840, James Prescott Joule submitted to the Royal Society a paper describing experimental research on the heat produced by electric currents in metallic conductors, and inferring that the effect was proportional to the resistance of the conductors and to the square of the intensity of the current. Only an abstract of this paper was published in the Proceedings of the Royal Society , although a full paper with a similar title was printed in the Philosophical Magazine in 1841. Several authors have assumed that the content of the 1841 publication was the same as the rejected 1840 paper; however, the unpublished manuscript has been found within the archives of the Royal Society and is published here for the first time, along with a detailed analysis and comparison with the 1841 paper. The unpublished version is much shorter, and is different in certain respects from the published article. A detailed comparison throws light on several shortcomings of the unpublished version. The present work also studies the assessment of Joule's paper by the Royal Society, and elucidates the roles of Peter Roget and Samuel Christie in this connection.

Este depoimento descreve as tentativas e dificuldades de obtenção de acesso à documentação inédita de um astrônomo suíço, Leopold Courvoisier (1873-1955). Esses documentos seriam importantes para esclarecer diversas questões historiográficas, mas uma parte deles foi destruída durante a Segunda Guerra Mundial e outra parte se perdeu ou ficou inacessível por decisão da família do pesquisador.

In his celebrated historic-epistemological work Identite et realite, Emile Meyerson claimed that the scientific conservation principles were first suggested and accepted for philosophical reasons, and only afterwards were submitted to experimental tests. One of the instances he discussed in his book is the principle of mass conservation in chemical reactions. Meyerson pointed out that several authors, from Antiquity to Kant, accepted the idea of quantitative conservation of matter; and Lavoisier himself was strongly influenced by a priori ideas, using this principle instead of attempting to test it. This paper will review Meyerson’s claim and historic evidence, focusing especially the late nineteenth and early twentieth century, when the principle of mass conservation was tested in highly accurate experiments. Instead of confirming the principle, some of those experiments led to the detection of anomalies. Hans Landolt, for instance, noticed that there were some small violations of the principle. He observed mass variations of about 10−6 in chemical reactions produced in hermetically sealed glass tubes. Since Landolt was a famous chemist, his results produced a strong response. Several researchers repeated his experiments, with different results. Landolt himself improved his experiments, with a balance that could detect mass changes of 10−7. After changes of the experimental procedure, the chemical reactions did not show significant mass changes. There was not, however, any “crucial experiment” “proving” that mass was conserved. The observed anomalies were set aside mainly by theoretical reasons, after the discovery of radioactivity and the development of the theory of relativity.

This work describes a strategy for teaching the history of science that contrasts different types of historical resources, including pieces of pseudohistory, with primary and secondary sources. This approach provides lessons and stimulates attitudes that are very difficult to overcome using other tactics. Notably, one of the aims of this method is to teach the students how to distinguish a well-grounded historical narrative from an unreliable one and to develop a critical attitude concerning the flawed stories that proliferate on the internet and in popular science books. Besides describing the general procedure used at a Brazilian university, the paper presents its exemplification in the study of Hans Christian Orsted’s discovery of electromagnetism.

Este artigo expõe o desenvolvimento sobre o conhecimento medieval a respeito do magnetismo, dando especial ênfase aos estudos de Petrus Peregrinus (Pierre de Maricourt). Este autor muito importante, mas pouco conhecido, escreveu a obra mais antiga que conhecemos (1269) onde aparecem os conceitos de polos magnéticos e as leis qualitativas de atração e repulsão entre eles. A parte final deste artigo contém uma tradução completa, feita a partir do texto latino, da "Epistola de magnete" desse autor, através da qual é possível perceber que Petrus Peregrinus realizou um estudo experimental sobre o magnetismo. O estudo de sua contribuição pode ajudar a superar alguns equívocos e preconceitos existentes sobre a ciência medieval. This paper presents the development of the medieval knowledge about magnetism, giving special attention to the studies of Petrus Peregrinus (Pierre de Maricourt). This very important but little known author wrote the oldest work known (1269) where the concept of magnetic poles and the qualitative laws of attraction and repulsion between them are described. The final part of this article contains a complete translation from Latin to Portuguese of the "Epistola de magnete" written by this author. By reading it one can realize that Petrus Peregrinus made an experimental investigation of magnetism. The study of his contribution may help to overcome some mistakes and the prejudices concerning medieval science.

This article presents the main results of a research examining the didactic transposition of history and philosophy of science in high school level. The adaptation of history of science to this particular level, addressing some aspects of the nature of science aiming at the students’ critical engagement, was analyzed by examining both the historiographic requirements of history of science and the pedagogical recommendations of science teaching. The research included the elaboration of a pilot course on the history of optics, with historical texts and educational activities, and its application in a high school. We used three episodes of the history of optics, addressing some epistemological points, especially criticizing the naive empirical-inductive view of science. It was possible to identify a series of obstacles in using history of science and conveying philosophical views. Their analysis resulted in devising strategies to surmount or to circumvent them. We implemented those strategies in the classroom and analyzed the data that was obtained. As a result, we substantiated several of our proposals and found that some solutions require improvement. We suggest some generalizations, which can be understood as initial parameters for guiding the use of history and philosophy of science in science teaching. We used a qualitative methodology of educational research to plan, to collect and to analyze the data, examining the interaction between students, teacher and knowledge.

This paper describes the early history of magnetochemistry: the search for chemical effects of magnetism in the nineteenth century. Some early researchers, such as Johann Wilhelm Ritter, attempted to reproduce with magnets the effects that had been produced by electricity and Volta’s battery. For several decades, researchers successively reported positive results and denied claims concerning the effect of magnetism in oxidation, electrolysis, reduction of metals from saline solutions, crystallisation, change of colour of vegetable tinctures and other chemical reactions. In the two last decades of the nineteenth century some effects were accepted as real, and a thermodynamic theory of the influence of magnetic fields upon chemical reactions was developed. Finally, Dragomir Hurmuzescu was able to create reproducible experiments and measured the electromotive force between two electrodes, with or without the presence of magnetic fields, confirming the existence of the phenomenon and obtaining results compatible with the theoretical predictions. Afterwards, this magnetochemical effect was accepted as real, but the effect was weak and its practical importance was negligible. The subject was gradually forgotten.

Vectors and quaternions are quite different mathematical quantities because they have different symmetry properties. Gibbs and Heaviside created their vector system starting from the quaternion system invented by Hamilton. They identified a pure quaternion as a vector and introduced some changes in the product of two vectors defined by Hamilton without realizing that the scalar product and vector product cannot be interpreted as the scalar part and vector part of the quaternion product. Toward the end of the 19th century some authors realized that there was an incompatibility between the vector and quaternion formalisms, but the central problem was not altogether clear. This paper will show that the main difficulty arose from Hamilton’s contradictory use of i, j, and k both as versors and as vectors.

The general aim of this paper is to elucidate some aspects of Newton's theory of light and colours, specially as presented in his first optical paper of 1672. This study analyzes Newton's main experiments intended to show that light is a mixture of rays with different refrangibilities. Although this theory is nowadays accepted and taught without discussion it is not as simple as it seems and many questions may arise in a critical study. Newton's theory of light and colour can be used as an example of the great care that must be taken when History of Science is applied to science teaching. An inadequate use of History of Science in education may convey to the students a wrong conception of scientific method and a mythical idea of science.

The common assumption that Becquerel had no special reason to study uranium compounds in his search for substances emitting penetrating radiation cannot explain (a) Becquerel's own accounts, which refer to his choice as due to “the peculiar harmonic series of bands”; (b) Becquerel's systematic test of all uranium compounds (and metallic uranium), in contrast to his neglect of other substances; and (c) Becquerel's belief in invisible phosphorescence as an explanation of the radiation emitted by uranium compounds, even after his discovery that non-luminescent and metallic uranium also emit penetrating radiation. By comparing Becquerel's older studies of uranium to his radioactivity research, this paper has presented a reconstruction that can explain all of these points above. According to the historical evidence presented here, it is likely that Becquerel concentrated his attention on uranium and its compounds because the mechanical theory of luminescence opened up the possibility that, precisely in the case of uranium and its compounds, a violation of Stokes's law could occur, and penetrating short-wavelength radiation could be emitted through a special type of phosphorescence.

This paper addresses the context of emergence, development, and current status of the use of history and philosophy of science in science education in Brazil. After a short overview of the three areas (history of science, philosophy of science, and science education) in Brazil, the paper focuses on the application of this approach to teaching physics, chemistry, and biology at the secondary school level. The first Brazilian researches along this line appeared more consistently in the decade of 1970. From 1980 onwards, the importance of this approach became widely accepted, and the subject became a common theme of dissertations and theses, appearing in conferences and educational journals. Since 1998, the use of history and philosophy of science was included among the government recommendations for secondary school science teaching in Brazil. Nowadays, this is an important line of research in graduate programs on science and mathematics education. However, the actual use of this approach in secondary education is still a desideratum.

SUMMARY This report presents a bibliographical project on sources for the study of Portuguese and Brazilian science, medicine and technology, from the 15th century to 1900. The project has led to the development of a set of computerized databases containing 40,000 entries on primary and secondary sources (including printed works, manuscripts, and maps).

Heron de Alexandria utilizou o princípio do caminho mínimo para explicar a reflexão em espelhos planos e curvos. No caso dos curvos, o princípio apenas é válido para espelhos convexos. Este artigo apresenta um histórico do princípio de Heron e de suas críticas no período moderno, discutindo os limites de validade desse princípio. Hero of Alexandria used the principle of minimum path to explain reflection in plane and curved mirrors. In the case of curved ones, the principle is valid only for convex mirrors. This paper presents a history of Hero's principle and of its criticism during the early modern period, discussing the limits of legitimacy of the principle.

In his early papers, Becquerel interpreted the emission of penetrating radiation by uranium and its compounds as a type of invisible phosphorescence, with emission of some kind of electromagnetic radiation. He devised experiments that seemed to confirm his interpretation and that were later disconfirmed by other researchers. This paper analyses the early history of radioactivity, paying special attention to Becquerel’s mistakes and to the attitude of other scientists to his work.

s of Erdmann’s paper soon appeared in French and in English. As had happened in the case of Paul Ermann’s 1807 paper, his experiments seemed convincing and were cited by several authors as a definitive proof that magnetism had no influence on chemical phenomena.

Maupertuis propôs, em 1744, o ''princípio da ação mínima'', aplicando-o à refração da luz. Este artigo discute a fundamentação deste trabalho de Maupertuis, bem como as críticas que recebeu por parte de d'Alembert e d'Arcy. A presente análise mostra que não havia uma boa fundamentação para a proposta do princípio de ação mínima, já que a reflexão e a refração da luz não obedecem a um princípio geral de mínimo. Maupertuis proposed in 1744 the ''principle of least action'', applying it to the refraction of light. This paper discusses the foundation of Maupertuis' work and the criticism it received from d'Alembert and d'Arcy. This analysis shows that the principle of least action was not well grounded, since the reflection and refraction of light do not obey a general principle of minimum.

Neste artigo, discutiremos o trabalho sobre luz e cores de Newton publicado em 1672 para vermos exemplos de questões que podem ser abordadas em sala de aula através da História da Ciência. No entanto, alguns cuidados devem ser tomados para não apresentarmos uma visão distorcida do método científico e uma idéia mítica sobre a Ciência. Este estudo analisa o experimento principal de Newton cuja intenção era mostrar que a luz branca é uma mistura de raios com diferentes refrangibilidades. Embora atualmente essa teoria seja aceita e ensinada sem discussão, um estudo histórico crítico sobre ela levanta muitas questões que serão discutidas neste artigo. This paper analyses some features of Newton's theory of light and colors, especially as presented in his paper of 1672, as an example of the classroom use of History of Science. Although this theory is nowadays accepted and taught without discussion, it is not so simple as it seems and many questions arise from a critical study. Besides, an inadequate use of History of Science in Science Teaching may convey to the students a wrong conception of the scientific method.

The general aim of this paper is to elucidate some aspects of Newton’s theory of light and colours, specially as presented in his first optical paper of 1672. This study analyzes Newton’s main experiments intended to show that light is a mixture of rays with different refrangibilities. Although this theory is nowadays accepted and taught without discussion it is not as simple as it seems and many questions may arise in a critical study. Newton’s theory of light and colour can be used as an example of the great care that must be taken when History of Science is applied to science teaching. An inadequate use of History of Science in education may convey to the students a wrong conception of scientific method and a mythical idea of science.

Este artigo discute a possibilidade do vácuo absoluto - ou seja, de um espaço no qual não exista qualquer substância. A motivação desse estudo é o contraste entre a quase unanimidade dos filósofos, até Descartes, contra a possibilidade do vácuo - e a mudança ocorrida no século XVII, quando, a partir de estudos experimentais de Torricelli e Pascal, passou-se a aceitar a possibilidade e existência efetiva do vácuo. Contrariando a opinião atual mais comum, este artigo procura mostrar que uma concepção hoje em descrédito na ciência - a de um éter - é preferível à concepção de um vácuo, por vários motivos. Em primeiro lugar, porque não se pode mostrar, empiricamente, que o éter não existe; em segundo lugar, porque um vácuo é impensável; em terceiro, porque a concepção de um éter é útil à compreensão dos fenômenos físicos; e, em quarto lugar, porque a hipótese da existência de um éter em espaços aparentemente vazios é útil ao progresso futuro da ciência. O artigo procura mostrar também que nenhum avanço recente da ciência alterou essas antigas conclusões e que nenhum avanço futuro pode alterá-las. This paper discusses the possibility of an absolute vacuum - a space without any substance. The motivation of this study is the contrast between most philosophers, up to Descartes, who stated that a vacuum was impossible, and the 17th century change of outlook, when the possibility and effective existence of the vacuum was accepted after the experiments ofTorricelli and Pascal. This article attempts to show that, contrary to the received opinion, the acceptance of an ether is preferable to the acceptance of a vacuum for several reasons. First: it is impossible to provide an empirical proof of the non-existence of the ether; second, an absolute vacuum is unthinkable; third, the ether concept is useful for the understanding of physical phaenomena; and fourth, the hypothesis of an ether in apparently void spaces is useful for the future development of science. The paper also endeavours to show that no recent advance of science has changed those conclusions and that no future development can change them.

The light pencil emitted by a rotating beacon may produce at great distances a spot of light moving with superluminal speed. This light spot may be used for synchronization of distant clocks, and this method would seem to provide an absolute criterion for simultaneity due to an invariant feature of rotation. This conjecture is explored and then contrasted with another argument that denies that such synchronization is absolute. The shortcomings of the first argument are discussed, and it is shown that this process is equivalent to the usual synchronization by light signals.

The apparent self‐contradictions of special relativity in thought experiments, where a body is intended to traverse a slit, do not have so simple a solution when that object is three‐dimensional as when it is an idealized one‐ or bi‐dimensional body. We use a special case of this new kind of situation in order to exemplify the general method whereby any such paradox may be analyzed and shown to be no real contradiction.

Louis de Broglie’s original theory of matter waves has until very recently received relatively little treatment in the literature on history and foundations of physics. This paper attempts to clarify a number of aspects of de Broglie’s theory, as formulated primarily in his famous thesis, which still give rise to confusion or debate. To this end, a re‐examination is made of the scope and validity of the relativistic physics employed in de Broglie’s arguments concerning the existence of phase waves and their physical implications. Recent doubts concerning the soundness of de Broglie’s introduction of a wave group associated with the quantum are also analyzed in detail, and it is argued that the wave group indeed has a problematic, if minor, role in the overall theory.

A paper by Macagno (3) in this Journal is discussed. The origin of the concept of physical dimensions is traced back to ideas previously used in analytic geometry. Descartes' use of the word “dimension” in the study of physical magnitudes is shown to have properties completely different from Fourier's dimensions, being therefore unimportant to the evolution of dimensional analysis. It is also shown that the principle of homogeneity was used in the derivation of physical equations sixty years prior to the publication of Fourier's work, and that the latter was aware of this paper, that may be considered the earliest publication on dimensional analysis.

Relativistic dynamics has been historically built without an immediate connection to empirical operations. In order to test dynamic laws by experiment, it is necessary that at least one dynamic parameter be made measurable for moving systems. A method of force measurements applicable to moving systems is proposed. It is shown with the aid of thought experiments that the method leads to the accepted relativistic force transformations.

A maioria dos resultados da dinâmica relativística já havia sido obtida antes do artigo de Einstein de 1905. A partir do eletromagnetismo, já haviam sido obtidas relações entre massa e velocidade, e massa e energia. Esses desenvolvimentos foram devidos a uma crença generalizada no éter como sendo uma realidade física capaz de produzir forças e que era dotado de propriedades mecânicas como massa, energia e momento. Este artigo descreve o desenvolvimento dessas idéias e compara os resultados obtidos pelos partidários do éter com as propostas de Einstein. Most of the results of relativistic dynamics had already been obtained before Einstein's 1905 paper. Relations between mass and velocity, and mass and energy, had already been obtained from electromagnetic theory. Those developments were due to a widespread belief in the ether as a physical reality, that could produce forces and was endowed with mechanical properties such as mass, energy and momentum. This paper describes the development of those ideas and compares the results obtained by the ether partisans and Einstein's proposals.

Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Filosofia e Ciencias Humanas Resumo: Os desiderata constituem um tipo de categoria axiológica representando aquilo a que se dá um valor positivo, sem no entanto adquirir o caráter de imposição. Representam condições suficientes mas não necessárias para que se atribua valor positivo a algo. Na prática científica e epistemológica usualmente se torna necessário avaliar procedimentos e resultados científicos. Em algumas abordagens epistemológicas, procura-se formular regras de avaliação fundamentadas em exigências rígidas, do tipo: ¿x é aceitável, cientificamente, se e somente se y¿, que apresentam condições necessárias e suficientes para que algo receba um valor científico positivo. O uso do conceito de desiteratum, mais fraco do que a idéia de uma demarcação entre ciência e não-ciência, permite uma análise mais flexível. A tese contém um estudo analítico do conceito de desideratum, sua relação com outros conceitos axiológicos e a estrutura geral de uma axiologia da ciência aplicando tais conceitos. Após o estudo analítico são examinados exemplos históricos confrontando-se as abordagens metodológicas existentes com a abordagem não proibitiva que faz uso de desiderata. Por fim, é proposto um sistema metodológico compatível com essa abordagem e são discutidas suas bases e conseqüências Abstract: Not informed Doutorado Doutor em Filosofia