The "natural nitrary" of Pulo di Molfetta The name of Giuseppe Maria Giovene is inextricably linked to the discovery of the so-called "natural
nitrary" (, which means a natural deposit of
saltpetre) of
Pulo di Molfetta. In 1783, abbot
Alberto Fortis visited
Apulia in order to study the region, and
Ciro Saverio Minervini appointed Giovene as Fortis' guide. On this occasion, Fortis and Giovene met, and Giovene later told Alberto Fortis about a doline of that region called
Pulo di Molfetta, in which Giovene believed that there was
saltpetre. After an inspection, Fortis noted that Giovene had been right and that there was saltpetre in that doline. According to other sources, however, Fortis and Giovene together discovered the "natural nitrary". According to
Zimmermann, the discovery was made by
Alberto Fortis, and Giovene just told Fortis about
Pulo di Molfetta and accompanied him. The discovery also generated issues; in particular, the discovery was initially challenged by some scholars. Subsequently, chemist
Giuseppe Vairo and his assistant
Antonio Pitaro confirmed the discovery. This undoubtedly damaged producers of artificial saltpetre, and some scholars, most likely supported by the producers, tried to dismiss the discovery. Following the discovery, a large number of naturalists sent by academies from all Europe came to visit
Pulo di Molfetta, since the saltpeter was a fundamental ingredient in the production of
gunpowder and that these deposits were of considerable strategic interest. In particular, in a letter to
Alberto Fortis dated 7 August 1784, Giovene refuted the idea of those who believed that the
saltpetre of
Pulo di Molfetta was due to some animals that once inhabited the doline. He also proved to be a talented chemist, and to be even more competent than the salt pans themselves, teaching them to correct the acidity of the ground (containing excessive amounts of "
azotic acid") by adding plant ash. During a trip with his brother over
Apulia, Giovene noted that saltpetre was abundant in other areas of
Apulia. The trip, together with Giovene's observations were reported in the aforementioned letter of 7 August 1784.
Agronomy and meteorology In some of his writings, Giovene also studied a disease of olive trees caused by
Pseudomonas savastanoi (in Italian, the disease is called ''rogna dell'ulivo''). The disease can be recognized by the characteristic
tumour. In particular, Giovene recognized that the disease was not caused by insects, although the insects formed. He also distinguished the tumours caused by frost from those generated by hail or blunt bodies. He also carried out some experiments where he boiled branches attacked by the disease, and he came to the conclusion that the tumours which weren't caused by frost were "germs of new twigs or branches suffocated in their birth". He came to this conclusion by cutting the tumours and observing the center. He also studied the worms and insects that "corrode and ravage the orchard." During his life he also carried out research in
meteorology. After the discovery of the "natural nitrary", scholars from many European academies came to Molfetta, and Giovene took the opportunity to meet and discuss with many of them. One of these was
Giuseppe Toaldo, who made him interested in
meteorology, as a science useful to regulate agriculture. During his life, Giovene collected atmospheric, rainfall and barometric data, and studied their development. From 1788 to 1797, he wrote, for every year and starting from his observations, a memory of rainfall and their consequences on agriculture. Giovene was also praised by the most illustrious Italian meteorologist of that period,
Giuseppe Toaldo. In particular, if
Giuseppe Toaldo can well be considered the founder of Italian meteorology, Giovene may well consider himself the founder of Italian rural meteorology, so much so that he managed to make some eminent scholars of that period more interested in meteorology, including
Luca de Samuele Cagnazzi. In his study
Prospetto comparato della pioggia della Puglia (1805), Giovene asked his illustrious colleagues to obtain rainfall data for the nearby Apulian cities
Altamura,
Ariano,
Teramo, in addition to data from
Molfetta provided by Giovene himself.
Luca de Samuele Cagnazzi provided data for his city Altamura,
Giovanni Zerella provided data for Ariano, while
Orazio Delfico provided data for Teramo. With his study, Giovene wanted to prove that the amount of rainfall which fell on
Apulia wasn't that different from other European regions (such as some regions of France, which didn't have the same reputation of Apulia as a dry region). Although there are clear differences with other European regions more heavily watered by rain or with the South American city of
Santo Domingo, the biggest difference, according to Giovene, is due to the irregularity of rainfall events. One of the most innovative aspects of his meteorological studies is certainly that of comparing data that previously were not generally studied together, i.e. atmospheric electricity and atmospheric pressure. For these studies, culminating in his publication
Osservazioni elettro-atmosferiche e barometriche insieme paragonate (1798),
Carlo Amoretti stated that Giovene "had provided an invaluable service to meteorology and physics". Moreover, in the ''Discorso meteorologico-campestre per l'anno 1797'' (1798), Giovene had the brilliant and innovative idea that the exceptional event that occurred in 1797, i.e. drought continuing beyond the first days of August (in contrast with the observations of the previous years), could be caused by the decrease in
sunspots, which was observed by astronomers. he also wrote an annex to the above essay, in which he explained how his observations confirmed Van Swinden's conclusions on the correlation between
atmospheric pressure,
atmospheric electricity,
Aurora and oscillations of the Earth's magnetic field.
Rain dust Giuseppe Maria Giovene also correctly explained the phenomenon of the so-called red
rain dust (), fallen on
Apulia on 7 March 1803. It was believed at that time that the rain was caused by the explosion of Italy's volcanoes
Mount Vesuvius or
Etna, or that it was due to the transport of matter coming from the sea floor and raised by vapor. Giuseppe Maria Giovene brilliantly related the phenomenon to the wind occurred prior to the rain event, and he came to the conclusion that the sand came from Africa and that it had been pushed by the wind coming from south-east.
Entomology In a paper entitled '' Descrizione e storia della cocciniglia dell'ulivo'' (1807), Giovene also dealt with the insect "
Coccus oleae" (also "
Saissetia oleae"), answering
Giovanni Presta, who denied the existence of the insect in the provinces of
Bari and
Otranto. Giovene showed that the insect was widespread in those regions, albeit rarer. Moreover, Giovene also discovered the male of the cochineal, which wasn't known in much of Europe. In the "Dictionary of natural history" of Paris (1816) () it was written: "the male is not known" (). He also wrote the work
Avviso per la distruzione dei vermi che attaccano la polpa delle olive (1792), in which he provided some suggestions for the peasants in order to effectively destroy the worms
musca oleae, which infested the pulp of the
olive trees.
Dating the Earth Giuseppe Maria Giovene never hid his profound religiousness, as well as the contempt for atheism, which he considered to be true "dementia." He also based his assumptions on what was written in the Bible. In this regard, he criticized the new scientific theories according to which the Earth was actually much older than what was written in the
Bible. In some unpublished speeches held at the Academy of Catholic Religion in Rome (
Accademia di Religione Cattolica in Roma) –
Della pretesa antichità del tempo and ''Delle lave dell'Etna e degli argomenti che si pretende tirare per la molta antichità della Terra'' – he tried to refute those that Giovene considered distorted interpretations of
natural history. == Theology ==