The solar microscope of the collection of the Augustinian Recollects in the Museum of Sciences of the university of Navarre.

Manufactured in brass in the mid -nineteenth century, this curious microscope was used in the cabinet of sciences that served to train future Augustinian Recollect missionaries in the province of Saint Nicholas of Tolentine. Now he has raised the curiosity of the experts.

The Microbio page, dedicated to news and curiosities about viruses, bacteria and microbiology, and managed by Ignacio López-Goñi (Pamplona, 1962), microbiologist and scientific disseminator, doctor of Biology from the University of Navarre, has published a curious note about one of the elements donated to the University of Navarre Museum by the province of Saint Nicholas of Tolentine of the Order of Augustinian Recollects.

What caught the care of the scientist was specifically a solar microscope that is part from this collection, gathered in the nineteenth century by the Augustinian Recollects to train their futures missionaries and that includes, in addition to these observation and measurement objects, a good number of dissected animals. Today is very careful and accessible to visits in the museum of Sciences of the University of Navarre in Pamplona.

The solar microscope, as López-Goñi recalls, is made completely in brass and it takes the manufacturer’s registration at the base: “Breton. Fresh Avenue Victoria, 8. Paris”. By comparison with other similar microscopes is estimated that it should have been manufactured in the second half of the nineteenth century and was bought in Paris at the end of that century.

The solar microscope is actually a flashlight that works like a dark camera. Used as lighting the sun’s rays, redirected by a flat rotating mirror rectangular into the tube. It served to produce and project extended images of very small objects and was designed to handle in a dark room. Was fixed to the wall in such a way that the mirror was left on the outside to collect the sunlight and the rest of the artifact in the interior of the dark room in which the projection was going to be carried out. The sun’s rays to influence the mirror deviate through a cylinder towards a condenser lens and then towards a second lens where they concentrate at its focal point.

The object that will be observed is placed between two glass plates, which, by means of a spring, remains in a firm position between two metal plates. The object, strongly Illuminated, it is placed very close to the focus of a system of three condenser lenses.

Thus projected, on a screen or wall, and at an adequate distance, an inverted image and highly magnified. The distance of the lenses from the object is regulated by screws. As the direction of sunlight changes throughout the day, the position of the mirror can change and turn too. The solar microscope had the disadvantage of concentrating a lot of heat on the observed object, the that you could alter it quickly.

The precursor of this artifact was invented in 1733 by the German anatomist Nathanael Lieberkuhn (1711-1756) with a separate mirror that was oriented from outside the room for an assistant. The English Benjamin Martin coupled a mirror and John Cuff (1742) He added the adjustable rotating mechanism from inside the room.

In the second half of the 19th century, solar microscope exhibitions were organized in the that an entrance was charged to see large lice, fleas, bed bugs, insects of the cheese, drops of water or vinegar, boar bristles, hair or human hairs, blood and its circulation in animals … the increase could become up to 500,000 times.

The use of these projectors began to decline with the appearance of oxi- gas lamps hydrogen and electric arc, which produced intense light and allowed night demonstrations, not depending on sunlight.

The possession of these devices for the Augustinian Recollets starts from almost a century and a half ago. One of the religious trainers, Fray Pío Mareca, was entrusted to the purchase in Paris of a complete physics laboratory because – he said – “it is known that our religious physics students will advance much more by joining theory to practice. ”

From the mid -40s of the twentieth century, the Cabinet of Physics and Nature is transferred from Monteagudo’s novitiate (Navarre) to major and minor seminars from the province of Saint Nicholas of Tolentine in Marcilla (Navarre), Lodosa (Navarre), Fueguerrabía (Guipúzcoa) and Valladolid.

The year 2023 recovered the pieces that remained and delivered 93 to the Science Museum from the University of Navarre, where they have been reviewed, restored and made available to the interested public, such as Dr. Ignacio López-Goñi who has now reviewed this microscope.