1796: ?Pila?

1797: L’elettrometro condensatore, l’eliminazione dei

rivelatori organici, coppie bimetalliche

Rilevazione sbilancio del fluido senza la rana

200 hundred years ago: the “pile”• From a region, Lombardy, once again under

Austrian rule, the 20th of March 1800 a letter, written in French, is sent by an Italian scientist to the (British) Royal Society for publication in theTransactions. The author is not unknown, being a member of the Society and the recipient five years earlier of its Copley medal, but the letter is rather strange both in form and content: it claims nothing less than the discovery, today one would say the invention, of a perpetual electrical motion device, the “pile”; but rather than a proper scientific paper it is a collation of parts written in a great hurry.

• In this way the fifty-five year old Alessandro Volta, for twenty-two years professor of Experimental Physics, not of natural philosophy as reported in the Transactions, at Pavia University, communicated to the world the possibility of producing stable electrical currents, a result that was to change the way of life on this planet.

Letters to Banks

1799: Invention of the “pile”

• Mi procuro qualche dozzina di piccole lastre rotonde o dischi di rame, di ottone, o meglio di argento, di un pollice di diametro, più o meno (ad esempio, delle monete) ed un numero eguale di lastre di stagno, o, il che è molto meglio, di zinco, e presso a poco della medesima forma e grandezza: dico presso a poco perchè non è affatto richiesta una precisione, e, in generale, la grandezza, come la forma, dei pezzi metallici è arbitraria: bisogna soltanto aver riguardo di poterli disporre comodamente gli uni sopra gli altri in forma di colonna.

• Preparo inoltre un numero assai grande di dischi di cartone, di pelle, o di qualche altra materia spugnosa capace di assorbire e di ritenere molto dell'acqua o dell'umore di cui bisognerà, per il successo delle esperienze, che essi siano ben annacquati. Queste fette o dischi, che chiamerò dischi ammolliti, li faccio un po' più piccoli che i dischi o piastre metalliche, affinchè, interposti tra questi nel modo che dirò subito, essi non debordino.

Uno sguardo più accurato alla pila

• l’analogia con la torpedine

• i corpi organici come rivelatori

• la legge di Ohm

• il contatto bimetallico

• Qual è il modulo base della pila? La coppia bimetallica o il metallo-conduttore umido-metallo?

1799 : Volta inventa la pila

La pila: un ritorno ai rivelatori organici

• Volta ribadisce la fattorizzazione ma ha dei problemi

• I Francesi ribadiscono l’elettrostatica coulombiana

• Gli Inglesi sottolineano le reazioni chimiche

• Ancora oggi si dibatte

Volta: 1801-14 L’identità dei due fluidi

Accepting the battery• France: Coulombian electrostatics

– “Institut” not really in favour of Volta’s ideas

• Britain: Electrochemistry

• Germany: Interactions and unity of forces

Volta’s experimental contributions

• Electrophorus, electrometer, electric pistol, eudiometer, condenser, battery

Volta: 1799 La pilaCoppia bimetallica e conduttore umido

Volta’s conceptual contributions• Tension, charge, capacity; electromotive

force, current, resistance

• Factorisation of intensive and extensive factors Q=CT

Quantification and Qualification• The quantification of the Baconian sciences

did not follow only the non linear inverse square law of the Newtonian-Coulombian way. Linear quantification of qualities achieved through factorisation also played a relevant and lasting role

• For a fuller historical account the interplay between instruments and mathematics is not enough: we also need to focus on theoretical models and regulative principles

Volta’s theoretical legacy: a non standard but productive trend

• Alternative conceptual frameworks

– Oersted, Sadi Carnot, Faraday, Mayer

• Factorisation

– Ohm, Rankine, Ostwald, Helm,

– Duhem, Sommerfeld

• Later on: Theoretical Physics

– Helmholtz

Volta’s Theoretical Legacy• Ohm explicity referred to Volta and his law

is based on the product of an intensive (V) and extensive (1/R) quantity: Ohm’s law: I=V/R

• Carnot utilizes an approach similar to Volta’s one: the reestablishment of the equilibrium of the fluid (fire) through the tendency of an intensity factor (temperature)

Volta’s Theoretical Legacy• Volta’s concept of (atmo) sphere of activity

is echoed in Faraday’s electrotonic state, and the concept of vis attractiva in Faraday’s lines of force (flux tubes that attract and tend to enlarge). Lines of force, like vis attractiva, can also explain repulsion (attraction versus other bodies)

• Mayer in 1843 gives the first energy interpretation of the electrophorus

Volta’s Theoretical Legacy• Helmholtz’s in 1847 gives the first energy

interpretation of the contact of metals and of batteries. His struggle to separate the concept of Spannkraft (potential energy) from Newtonian Kraft echoes Volta’s struggle to introduce tension against force

• Rankine’s 1853 version of energy conservation (factorisation) is based on the product of an intensity factor by an extensive one

Volta’s Theoretical Legacy• Factorisation was a main part of the

energetics in the works of Ostwald, Helm and Duhem

• Sommerfeld still proposed this distinction in electromagnetism in the 1940’s, in his “advanced” textbook.

• And so we can close the hermeneutical Voltaic circle!!!

Volta’s Primary Sources• Archives

• Papers and Letters

• Instruments

Volta’s Sources: Archives

Istituto Lombardo di Scienze e Lettere

Volta’s Sources: Works

7 volumes: 1918-29

5 volumes: 1949-55 2 volumes: 1974-76

Volta’s Sources: Instruments

Museo per la Storia dell’Universitàdi Pavia

Tempio Voltiano-Como

Volta’s Sources: Instruments

Volta’s Sources: Instruments

Volta’s Sources: Instruments

Volta’s Historiography• A bit of history of historiography is

necessary

• Massardi and Polvani

• Heilbron

• Pera e Bernardi

• Pancaldi e Fregonese

The Received View• Classical sciences (general physics,

quadrivium) challenged by

• Baconian Sciences (particular, experimental physics)

• undergoing a process of quantification and mathematization along Newtonian-Coulombian lines

• Enlightenment and quantification

• “Standard Model” of particles and fluids and interactions

Volta’s Historiography: Massardi and Polvani

A triumphant march towards Coulomb’s approach

Volta’s Historiography: Pera and Bernardi

Volta’s Historiography: Pancaldi and Fregonese

• Giuliano Pancaldi:

• 1990: Electricity and Life. Volta’s Path to the Battery

• 1993: An Enlightened Physicist: Alessandro Volta and Electricity. 1745-1827

Volta’s celebrations• 1878 Pavia

• 1899 Como

• 1927 Como

• 1999 Pavia, Como

History of Celebrations: 1878 Pavia

• Laurea Honoris Causa: Helmholtz; Maxwell

Volta’s Celebrations: 1927 Como

Today

• The Cabinet and Multimedia

• Digitalising Collected Works and

Manuscripts

• Volta and the Web

• The “Nuova Voltiana”

The Cabinet and Multimedia

Digitalising Volta’s Sources

7 volumes: 1918-29

5 volumes: 1949-55 2 volumes: 1974-76

The Nuova Voltiana Restaging Volta’s Natural Philosophy

• There is a need for: a better understanding of Volta’s work in close connection with the path followed by the physical sciences from “natural philosophy” to the form and contents they assumed by the end of the eighteenth century.

• a more effective understanding of both his conceptual world and the extent to which it was embodied in the numerous instruments he invented.

Nuova Voltiana Journal of Voltaic Studies

• First Issues: papers presented at the WORKSHOP: Alessandro Volta between Natural

Philosophy, Chemistry and Physics

• December 1999

• Abbri: Volta’s chemical theories: The first two phases

• Agazzi: The impact of Alessandro Volta on German culture

• Bensaude: A glimpse on pneumatic chemistry from Pavia

Nuova Voltiana• Beretta: Volta and aerial medicine: Salubrity and

respirability of air at the end of the 18th century

• Bernardi: The controversy on animal electricity in eighteenth-century Italy: Galvani, Volta and other

protagonists

• Brambilla: Scientific and professional education in Lombardy, 1760-1803: Physics between medicine

and engineering

• Brenni-Bellodi: “The arms of the physicist” Volta and scientific instruments

Nuova Voltiana• Ciardi: Falling stars, instruments and myths.

Alessandro Volta and the birth of modern meteorology

• Gigli Berzolari: Volta's teaching in Como and Pavia: Moments of academic life under all flags

• Hackmann: The enigma of Volta’s ‘contact tension’ and the development of the ‘dry pile’

• Heilbron: Analogy in Volta's exact natural philosophy

• Holmes: Phlogiston in the air

Nuova Voltiana• Home: Volta’s English connections

• Hutchison: Forces and facts: Yet another fragment of the explanation for late 18C dynamism

• Kipnis: Debating the nature of the voltaic electricity, 1800-1850

• Kleinert: Volta and the German controversy about physics and Naturphilosophie, and Volta's relations

with Johann Wilhelm Ritter

• Kragh: Confusion and Controversy: Nineteenth-Century Theories of the Voltaic Pile

Nuova Voltiana• Martins: Romagnosi and Volta’s pile: Early

difficulties in the interpretation of voltaic electricity

• Pepe: Volta, the "Istituto Nazionale" and scientific communication in early 19th-century Italy

• Seligardi: Volta and the synthesis of water: Some reasons for a missed discovery

• Teichmann: Volta and the quantitative conceptualisation of electricity: From electrical

capacity to the preconception of Ohm’s law

Volta and the Web

• www.Cilea.it/Volta99

• Click “Alessandro Volta” and see:

• A biography

• The Cabinet

• The Collected Works

• A bibliography