Since I receive with regularity questions regarding De Pretto's paper, and its possible influence on Albert Einstein famous equation E = mc², and most of the relevant material is available only in Italian, I think useful to publish the full text of a recent interview with Dr Dhananjay Khadilkar (a science correspondent for DNA, "Daily News and Analysis", a Bombay based English daily).

Umberto Bartocci, Perugia, December 2005
 

Q1 Could you tell me about the man De Pretto? Who was he?

- Olinto De Pretto was born in Schio in the province of Vicenza in northern Italy on April 26, 1857. He was the sixth of the seven children of Pietro De Pretto (1810-1891) and Angelica Boschetti (1822-1905). The father was an architect in the town and dedicated himself also to the study of astronomy and geology. Upon graduating at the age of 22 with a degree in agronomics from the Superior School of Agriculture in Milano, Olinto became an university assistant to Professor Gaetano Cantoni in 1879. When Cantoni died in 1887, Olinto became the administrative director of a mechanical foundry mill owned by his older brother Silvio, and thereafter worked all his life in that factory, as a rather rich man. During the next year, he published his first work, "The Influence of the Raising and the Degradation of Mountains on the Development of Glaciers". He wrote this book because he was an amateur geologist and often went on alpine excursions with another brother, Augusto. Four years later, the three De Pretto brothers founded the Alpinistic Circle with Silvio as the first president. In 1896, his article was republished as "The Degradation of Mountains and Its Influence on Glaciers" in the Bulletin of the Italian Society of Geology. Two years later, his "Glacial Epoch and Orografical Theory" appeared in the Bulletin of the Italian Alpine Club. (Orology is the study of mountains.) In 1899, he had printed "Geological Signs in the Surroundings of Schio" in a local historical guide. At this time he began to pay attention to the emerging science of nuclear physics and its impact on astronomy. He studied as an amateur the subject for the next four years and took particular interest in the theory of aether, which was believed by most scientists of that time to fill the void in outer space. As a result of his studies, he wrote a paper entitled "Ipotesi dell'etere nella vita dell'universo", that is to say: Hypothesis of the Aether in the Life of the Universe". The article appeared on Nov. 29, 1903 in Atti del Reale Istituto Veneto di Scienze, Lettere ed Arti, vol. LXIII, namely: Procedings of the Royal Veneto Institute of Science, Letters and Arts. The work was endorsed by the illustrious astronomer Giovanni Schiaparelli (1835-1910). In this 62-page article, De Pretto attempted to prove the existence of the aether. During his study, he proposed that the formula mc² (with the modern notation c for the light speed) would measure the amount of energy contained in every material body of mass m, even if the body was at rest. Here are his words, in a personal translation:

"Nobody would easily admit that, stored in each kg of each mass, completely concealed to our investigations, there exists such an amount of energy, corresponding to the quantity of energy which can be obtained by millions and millions of Kg of coal; the idea would surely be considered as a foolish one".

(For the previous biographical sketch in English I am indebted with Dr Joseph Scafetta, and its publication of an article about De Pretto in "Fra Noi", Chicagoland's Italian American Voice, Sep. 2001).

Q2 When and in which publication was De Pretto's discovery first published?

- See before.

Q3 How did De Pretto happen to discover E=mc²?

- He thought that each body was simply made of "aether", in a particular state of motion (and density), and that the formula E = mc² was a measure of the energy of the aether stored in the body. BUT PLEASE LOOK CAREFULLY AT WHAT I WROTE IN THE WEB PAGE:

http://www.dipmat.unipg.it/~bartocci/fis/depr-engl.htm.

Q4 Did De Pretto get recognition for his discovery? If not, why?

- He got just little recognition, which is analysed in the section "Testimonianze su Olinto De Pretto" in the web page:

http://www.dipmat.unipg.it/~bartocci/st/depr-bonic.htm

(in this web page you could find a picture of De Pretto)

unfortunatey only in Italian, you should find some help for translating. The point is that De Pretto was just an outsider, not a physicist, nor an academician. Moreover his intuition was founded on a physical conception, the cartesian aether, which Einstein wept out from XXth century's physics. This explains the general oblivion about his hypothesis, and the fact that his work has never been object until now of the deserved attention from historians of science. One should not forget moreover that De Pretto very likely was not aware of Einstein's papers, as an outsider from Physics departments, and that when Einstein's reputation was increasing, and his name was worldwide known, De Pretto died (he died in 1921, and Einstein got his Nobel prize in 1922). Moreover, the relevance of the famous equation became clear only some years later, with the studies of Joliot-Curie, Fermi and others.

Q5 How did Einstein stumble upon De Pretto’s formula?

- It is very likely that Augusto De Pretto, another of Olinto's brothers, gave a copy of Olinto's article to his friend and co-worker, Beniamino Besso, who lived in Rome. Beniamino Besso sent it to his very dear nephew, Michele Angelo Besso, (Michele Angelo was guest at his uncle's house when an university student in Rome) who was a patent examiner in that same Swiss Patent Office in which Einstein at that time was working too. Michele Angelo Besso in my opinion could have given it to Einstein, who was, more than Besso's co-worker, Besso's close friend. Laurent Mousson, the head librarian at the Swiss Patent Office, has written about De Pretto's work that "we do not currently have this volume on our shelves". Nevertheless, he cautioned that the volume may have been available in 1905 and that it was later discarded. Anyway, there is no need that the whole volume in which De Pretto's essay was published should have been in the shelves of the Swiss Patent Office: it would have been enough for Besso to have a reprint of that paper, which surely Olinto's brother was happy to make circulate between friends. Interestingly enough, in his great article exposing the theory of relativity, written in 1905, Einstein acknowledged the help of only one person, that is to say Michele Angelo Besso.

Here it the "diagram" of a rather curious coincidence:

Olinto De Pretto <--> Augusto De Pretto brothers

Augusto De Pretto <--> Beniamino Besso co-workers and friends

Beniamino Besso <--> Michele Angelo Besso uncle and nephew

Michele Angelo Besso <--> Albert Einstein co-workers and friends.

Q6 Did Einstein lift De Pretto’s formula? Does this damage Einstein's reputation?

- In my personal reconstruction of this event, Einstein understood that De Pretto's idea was valuable, and realized that the formula proposed by de Pretto was compatible with his theory too. In other words, he took inspiration from De Pretto's bypothesis of the existence of a physically real great amount of energy stored in each body even at rest. Then he inserted the formula in his completely new relativistic approach, which was quite antithetical to the aether's approach followed by De Pretto. One should not forget, moreover, that the famous formula appears in a second shorter paper that Einstein published in the same year 1905, entitled "Ist die Trägheit eines Körpers von seinem Energiegehalt abhängig?", that is to say, Does the inertia (mass) of a body depend from its contents of energy?, with an interrogative mark. Einstein was not sure at all of this appendix to his previous greater relativity article, and wrote at that time at one of his friends something of the kind (I have no time for finding the exact reference): I do not know wheter the dear Lord is laughing after me about this matter.

As far as your second question is concerned, one must acknowledge that Einstein simply inserted De Pretto's idea in a quite different theoretical context. He could perhaps have behaved more correctly, quoting the Italian amateur (but doing so he would have even acknowledged the importance of the aether's theory, at least from an heuristic point of view), but he did not quote more influent scientists as Lorentz, Poincare', etc..

> Could you kindly send me a high resolution picture of yours

- http://www.dipmat.unipg.it/~bartocci/bartox.jpg

>> as well as the photo of the 1903 paper in which De Pretto's equation was published?

- http://www.dipmat.unipg.it/~bartocci/st/mem-depr-vf.htm

(in this web page, presenting the whole article of De Pretto, you could find also the image of the page in which De Pretto wrote his equation as mv², where v was the usual symbol at that time for the light speed, used by Einstein too).