In Europe during the 18th century demonstrations of physics experiments were not just carried out at the universities, but also in clubs, society meetings, in rooms rented by the so-called physics demonstrators – who journeyed around with their collection of tools – and in homes. It was not by chance that these experiments had gained scenic airs and the term theater was frequently associated with events of this type. There was an Experiments Theater, a Machinery Theater, the Experimental Physics Theater and the Poleni Theater, among others. “Then in the middle of the 17th century experimental practice, as a means of discovery and the validation of knowledge, began to take firm root”, advised Ermelinda Antunes, a researcher at the physics Department of the University of Coimbra (Portugal).
With this strong component of entertainment in the physics of that era, the Art Museum of the State of São Paulo has become the ideal place for the exhibition World Laboratory – ideas and knowledge of the 18th Century, which will go on until the 13th of March and of which professor Ermelinda is the curator. The exhibition involved a grouping of two hundred and twelve different units: scientific instruments and books from the 18th and 19th centuries – close to one hundred and ten of them belonging to the Physics Museum and the Astronomy Observatory of the University of Coimbra -, maps, pictures, engravings and paintings from the National Library archive at Rio de Janeiro.
The event integrates into the commemoration of the 450 Years of São Paulo city and is the result of a partnership between the Office of International Cultural Relations of the Culture Ministry in Portugal and the Sao Paulo Art Museum. The samples on show are at the center of various activities concerning the history of the 18th century. At the start of December an international seminar took place, entitled Lights in the tropics: the captaincy of São Paulo during the 18th century, coordinated by professors from the Jaime Cortesão Chair, an organ of the Philosophy, Letters and Human Sciences School of the University of São Paulo (USP), associated to the Camões Institute of the Portuguese Foreign Affairs Ministry. And, on the 25th of January an exposition entitled Cartography History in conjunction with USP’s Paulista Museum, on maps relating to the territory of the São Paulo captaincy era.
Of all of the events, the World Laboratory is that which most expresses the change of paradigms and the adoption of new ideas during an era in which abandoning ancient theories concerning the natural world, based on Aristotle, had begun very slowly. “The value of experimentation had been defended by Sir Francis Bacon in his work Novum Organum, published in 1620, in which said that “progress could only result from a close and strict union between rational and experimental faculties, which up until then had never been united””, says Ermelinda. During the 18th century natural phenomena had become looked upon as a mixture of material and forces and were to be described in mathematical language.
The instrument took on great importance in the task of interrogating nature, and not just as a sample of the creative capacity of man. “Utensils such as air pumps, interconnected receptacles or apparatus for pumping water, used since antiquity, were perfected and became scientific instruments, put to work in the resolution of fundamental problems” It was during the 17th century that the curiosity rooms and the theaters dealing with machinery appeared. They were the ones that gave origin during the following century to the physics rooms within universities There is, nevertheless, a natural development towards the construction of the so called philosophical instruments, made with the finality of producing and demonstrating the various effects of physics.
The Art Museum exhibition tells part of this history. There are simple instruments such as Musschenbroek’s crank, used to raise heavy loads, and others that are more sophisticated such as the paralytic telescope, destined to follow the parallel of a star or its nightly movement from east to west, describing its same parallel. There are set-ups that, since they are so prosaic, bring a smile to the visitor. This is the case of a educational model of a screw with a wound on nut, which can be divided into two parts, or a press used to verify the compressibility of water. This was the era of the study of simple and compound movement, of projectile trajectories and of different types of force and their effects.
In the collection from the University of Coimbra there are also some famous curiosities, such as “the powerful dark magnet set in a crown.” In this case it is simply a large magnet “dressed” with a royal crown with which the force of magnetic stones had been demonstrated. This one in particular was capable was sustaining 93.7 kilograms. In the exhibition there is a piece of furniture that does not belong to the University of Coimbra, but which calls one’s attention: the acoustic throne made in 1819 to mitigate the deafness of Don João VI, one of the most ingenious pieces ever to have been built for this means.
Some demonstrations done inside and outside of the university have delighted the general public. Those that involved electricity, such as the luminous and noisy electrostatic experiments were much appreciated. Or there is the pump that extracted air and created a vacuum within the two copper hemispheres, invented by Otto de Guericke in the 17th century. The story of the famous experiment done by him in 1657 with these two hemispheres, which were only able to be separated by the force of eight pairs of horses, spread throughout all of Europe (a replica of the so called Magdeburg hemispheres are in the exhibition). Another type of experiment that managed to have immediate practical use is that of the lightning rod model, made between 1790 and 1824. In an explanatory book whose author is the Italian professor Giannantonio dalla Bella, Historical and practical news dealing with the means of defending buildings from lightning damage, it states how to protect gunpowder storerooms and gives the best method of installing the rod.
Out of the one hundred and ten tools that came from Portugal, Ermelinda Antunes risked a guess on what she considered to be the most valuable from the point of view of the history of science: Volta’s battery form 1800, the first generator of electrical current. However, there are other important items. “Man’s efforts in the setting out of knowledge involves generations”, stated the Portuguese researcher. “One might note three pieces present in the sample: the aeolipile, Botelho Lacerda’s rotary drill and the train”, she gave as examples. The aeolipile machine is a hollow metal ball with water mounted in a trailer. When warmed, the water vaporizes and makes the trailer move. Botelho Lacerda’s rotary drill demonstrates the action of vapor to be used as a mechanical force. And the train is well known. “All of them make up part of the history of the use of the motor effects from a vapor jet, already known in Ancient Greece. There is no point in saying which is the most important.”
These instruments began to be studied in more depth in Portugal during the second half of the 18th century. Before then science had found itself in a precarious situation within the country. For sure there were Portuguese intellectuals enlightened and with knowledge of recent scientific advances. For example in 1737, the doctor of Jewish origin, Jacob de Castro Sarmento, who had settled in London, published the True Theory of Tides, the first book in Portuguese to publish Newton ideas. However, professor Ermelinda Antunes related that within the university, dominated by the Jesuits, the works and ideas of Galileu Galilei, Isaac Newton and Pierre Gassendi had been prohibited to circulate in 1746 through an edictal from the rector of the Arts College of Coimbra, father José Veloso.
When Sebastião José de Carvalho e Melo, the future Marquis of Pombal, was nominated by Don José I in 1750 as the King’s Minister, he was already conscious of the Portuguese lagging behind in this area. Pombal’s controversial administration touched all of the sectors of national life – and education was not left out. One of his initiatives, in 1761, was the founding of the Royal College of Nobles of the Court and the City of Lisbon, which admitted students from the Portuguese nobility between the ages of seven and thirteen. There, for the first time, scientific disciplines such as mathematics, astronomy and experimental physics were taught. It was to this college that Pombal invited Dalla Bella, then a professor at the University of Padua, in Italy, to give lessons and burdened him with the task of acquiring the necessary scientific instruments – the majority built by Portuguese craftsmen between 1766 and 1768 and some purchased from the English. “The Royal College of Nobles ended up not going well in the area of the sciences mainly due to the young age of the students and to the lack of their necessary base for understanding the material”, observes Ermelinda.
All of the instruments used in the lessons and in the physics experiments at the Royal College of Nobles were transferred to the Physics Office of the University of Coimbra in 1773 (one year before the start of the major university reform), where they gained in the organization and systematic use in lessons and experiments also commanded by professor Dalla Bella, who had been invited to assume the experimental physics chair. Part of this material is present in the World Laboratory exhibition. “The Physics Office used in the lessons at Coimbra, starting from 1773, had been perfectly well equipped to demonstrate physics of that era, at that time taught in France, England and Italy”, professor Ermelinda affirmed. With the university reform and the introduction of debate on the new scientific and philosophical theories, Portugal gained new status. And hence it penetrated into the world of ideas and knowledge of the 18th century.
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