Editing Electromotive force (section)

====Voltaic cells====
Volta developed the voltaic cell about 1792, and presented his work March 20, 1800.<ref name=Mottelay>{{cite book |title=Bibliographical History of Electricity and Magnetism |first=Paul Fleury|last=Mottelay |page=247 |url=https://books.google.com/books?id=9vzti90Q8i0C&pg=RA1-PA247 |isbn=978-1-4437-2844-7 |publisher=Read Books |year=2008 |edition=Reprint of 1892}}</ref> Volta correctly identified the role of dissimilar electrodes in producing the voltage, but incorrectly dismissed any role for the electrolyte.<ref name=Kragh>{{cite journal
 |journal     = Nuova Voltiana:Studies on Volta and His Times
 |publisher   = Università degli studi di Pavia
 |year        = 2000
 |url         = http://ppp.unipv.it/Collana/Pages/Libri/Saggi/NuovaVoltiana_PDF/sei.pdf
 |title       = Confusion and Controversy: Nineteenth-century theories of the voltaic pile
 |first = Helge|last=Kragh
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20090320064922/http://ppp.unipv.it/Collana/Pages/Libri/Saggi/NuovaVoltiana_PDF/sei.pdf
 |archive-date = 2009-03-20
}}</ref> Volta ordered the metals in a 'tension series', "that is to say in an order such that any one in the list becomes positive when in contact with any one that succeeds, but negative by contact with any one that precedes it."<ref name=Cumming>{{cite book |title=An Introduction to the Theory of Electricity |first=Linnaus|last=Cumming |url=https://books.google.com/books?id=Nrb8723u4WEC&pg=PA118 |page=118 |isbn=978-0-559-20742-6 |publisher=BiblioBazaar |year=2008 |edition=Reprint of 1885}}</ref> A typical symbolic convention in a schematic of this circuit ( –<big>|</big>'''<small>|</small>'''– ) would have a long electrode 1 and a short electrode 2, to indicate that electrode 1 dominates.  Volta's law about opposing electrode emfs implies that, given ten electrodes (for example, zinc and nine other materials), 45 unique combinations of voltaic cells (10 × 9/2) can be created.