The Pacinotti Fund, a heritage of science and innovation at the Museum of Physics Instruments in Pisa

The Museum of Physics Instruments at the University of Pisa is one of the most prestigious institutions in Italy for the preservation and study of the history of science and physics. It is here that a unique and valuable core collection is preserved within: the Pacinotti Fund, a collection of historical scientific instruments that represents a fundamental reference point for understanding the evolution of physics and technology. This fund is named after the Pisan engineer and physicist Antonio Pacinotti (Pisa, 1841 - 1912), who left an indelible mark on the history of science, both for his discoveries and his commitment to scientific education.

Pacinotti was born in Pisa in 1841 and distinguished himself from a young age for his intellectual gifts, so much so that as early as 1861, when he was only 20 years old, he graduated from the University of Pisa with a degree in Applied Mathematics. His professional career was marked by a deep interest in electricity and its applications, a topic that was emerging strongly in the international scientific community at that time. Pacinotti, along with other scientists of the time, contributed significantly to the development of the theory and applications of electricity, but he is mainly remembered for his perfection of his direct-current motor, an invention that foreshadowed the future of electric generation.

In fact, Pacinotti made one of the first versions of what would later become the dynamoelectric machine, the electric generator that would revolutionize the world of technology. His invention contributed greatly to the spread of electrical technologies in Europe, marking the beginning of a new industrial era. Pacinotti’s machine was, among other things, one of the first to enable the efficient and stable production of direct electric current. And his dynamo is considered the first machine in history capable of producing electricity: it was an important evolution from the batteries and batteries that, until 1859, when Pacinotti, at only eighteen years of age, devised his invention, were the only tools for producing electricity.

The Pacinotti Fund: a historical collection of scientific instruments

The Pacinotti Fund at the Museum of Physics Instruments at the University of Pisa is a collection of scientific objects that testify to the evolution of physics and its applications. Among the objects that make up the collection are instruments of great historical and scientific value, many of which were used by Pacinotti himself during his experiments and discoveries.

he Fund includes a wide range of scientific equipment, including laboratory instruments, apparatus for experiments in electromagnetism, and machines that represent the culmination of the research of Pacinotti and his contemporaries. Each instrument tells a story, that of scientific research that marked the evolution of thought and technology.

The collection consists mainly of instruments dealing with electromagnetism and mechanics, areas of study in which Pacinotti made important advances. Among the most significant items in the collection are various types of magnets, coils, and apparatus for producing electric current, but also precision instruments used to measure physical phenomena such as voltage, current, and resistance. Each instrument is a tangible witness to the progress of physics in the 19th century, a period that saw the transition from philosophical theories of nature to practical applications of scientific discoveries.

In addition to this, the Pacinotti Fund also holds a number of scientific publications, letters and documents that chronicle the life and work of the Pisan physicist, as well as his relationships with other scholars and his influence on subsequent generations. These documents, some of which are unpublished, constitute a valuable source for historical research, and offer insights to better understand the scientific context of the time and Pacinotti’s contribution to the growth of modern physics.

What instruments can be found in the Pacinotti Fund.

Among the most interesting instruments in the fund are certainly Pacinotti’s rings: they were used by the scientist for the first technical tests that led to the creation of the ring electromagnetic machine, also called “transverse magnet.” Another important device is Pacinotti’s macchinetta, built in 1860 after the inventor had briefly interrupted the project due to his participation in the Second War of Independence. Despite the interruption, Pacinotti continued to think about the project during the war period. After his return to Pisa, and with the help of a mechanic, he completed the machine, which had only one fixed electromagnet. This machine proved effective both as a motor and as a dynamo, producing a very intense direct current. The machine used a system of windings and collectors, and was distinguished by its ability to generate a constant current without the need for external permanent magnets. “The electro-magnetic machine of which the first ideas are found recorded above,” Pacinotti wrote in his book Dreams, “was built by me in small model form; [...] This machine has only one fixed electro magnet. It acts very well as an electric magneto machine, since it gives a continuous current always in one direction and very intense.”

Again, the “electromagnetic avenue” or “rifle” represented a prototype linear motor used for ballistics experiments. Using electromagnets mounted in series and properly powered, Pacinotti attempted to explore the possibility of firing projectiles by means of electric current, an experiment that showed his innovative vision. Other inventions include tripod disks, used by Pacinotti for experiments on electricity generated by rubbing between pairs of different materials. These tripods were built in various models, some of which have been restored to provide accurate information about the configuration of the experiments. Another interesting device is the wood lathe, a foot-powered machine tool that was used for the construction of cylindrical-shaped objects, such as furniture legs and other trimmings. This lathe, which was located in Pacinotti’s workshop, was particularly useful for building the wooden supports for Pacinotti’s rings and other components used in his inventions.

The ring-magnet motor was similar to Pacinotti’s little machine, but it lacked the crank that would have allowed it to function as a dynamo. This device had a mainly demonstrative function and was used in some photographs showing Pacinotti with the machine. Another of Pacinotti’s creations was the “double-belt electromagnetic” tramway car model. This was a scaled-down prototype of a car with linear electromagnetic traction. The system used employed two iron structures along the sides of the car, which contained solenoids powered by contacts on the track sleepers. This experiment was aimed at studying mechanical reliability, safety and the possibility of varying the speed of the vehicle using the magnet system. Mention can then be made of the electrodynamic translatory electromagnetic tether machine, another prototype for the electromagnetically driven vehicle. The system was based on a trolley running through a tunnel on three “V” tracks, with electromagnets arranged along the way interacting with the trolley, which was powered by an electric current.

Another device, the Ladd system electromagnetic machine, was designed to produce direct current by using a crank to rotate two Siemens armatures within a magnetic field. Pacinotti built it to compare with his 1860 “little machine.” Then one encounters the electromagnetic machine with superexciter, a later version of the “macchinetta,” but with a distinctive feature: a switch mounted on axis with the rotating magnet. This device increased the efficiency of current production by opening and closing the switch, twice for each revolution of the rotor. The magneto-electric ball machine, another of his designs, was also similar to the “little machine,” but with an innovation in the winding of the wire on the rotating magnet. This type of winding, similar to that used for cotton balls, made it possible to optimize space and increase the efficiency of the machine.

The angle diverter, on the other hand, was a device used to detect angles from a distance. It operated by means of a circular electromagnet that, in combination with an indicator, transmitted angular variations at a distance, also enabling practical applications such as remote control of valves or ships’ rudders. Finally, mention can be made of the apparatusfor the study of electric currents, a piece of equipment that allowed the scientist to experiment with the production of electric currents with a rotating flywheel in copper sectors that was in serried in a magnetic field.

Enhancement and the future of the Pacinotti Fund

The Pacinotti Fund is a heritage of inestimable value, but like all historical collections it requires ongoing conservation and enhancement work. The University of Pisa and the Museum of Physics Instruments are constantly engaged in restoration and digitization projects to preserve the instruments and make them known to new generations of scholars and researchers. In particular, the digitization of the collections offers new opportunities for the study and dissemination of scientific heritage, allowing anyone to access, even remotely, the museum’s historical resources. Together with the Galilei Foundation, the Museum of Physics Instruments has therefore networked the machines in the collection, which have also been recently restored, and for each one, photographs are provided, the operation is described, and the restoration work is explained, also documenting the state before restoration.

In addition, the Pacinotti Fund is at the center of research activities involving historians of science, engineers, and physicists, who use the instruments and documents preserved in the museum to deepen their understanding of 19th-century scientific techniques and theories. This type of research is fundamental to understanding not only the history of science, but also the roots of the technological innovations that shaped the modern world. The Pacinotti Fund represents one of the most significant resources for the history of physics and technology, a heritage that chronicles the genesis of the discoveries that marked the transition from classical to modern science. Its preservation within the Museum of Physics Instruments at the University of Pisa thus allows the memory of a great scientist and his discoveries to be preserved for future generations.

The Pacinotti Fund, a heritage of science and innovation at the Museum of Physics Instruments in Pisa

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