May 1, 1827

Die galvanische Kette, mathematisch bearbeitet

Georg Ohm's mathematical theory of the galvanic circuit appears in Berlin

The famous 1 May date comes from the last line of Ohm's preface, not from any publication notice — and the law in the book had already appeared in his 1826 papers.

May 1827: a book out of Berlin

Georg Simon Ohm dated the preface of Die galvanische Kette, mathematisch bearbeitet at Berlin on 1 May 1827. The date is printed beneath the preface and is not identified there as the book's retail publication date.

T. H. Riemann published the 245-page volume in Berlin in 1827; a German biographical source says it appeared during May. Catalogues generally give only the year, and no consulted bibliographic source independently identifies 1 May as the publication or sale date.

What the book set out to do

Ohm presented a fully developed mathematical theory meant to unify galvanic phenomena arising from contact between different bodies, beginning with one-dimensional conduction.

Roughly the first third is a substantially geometric introduction aimed at readers less comfortable with advanced mathematics; the rest develops a more rigorous deductive theory built on three fundamental laws.

He had modelled parts of the treatment on Joseph Fourier's mathematics of heat conduction.

Not the first appearance of Ohm's law

The relationship now called Ohm's law did not debut here. His February 1826 paper had already announced the comprehensive current relationship X = a/(b+x), and another 1826 paper gave the equivalent reduced-length form X = a/l.

Those earlier experiments used a thermoelectric source, suggested by Johann Christian Poggendorff, because fluctuating voltaic piles had initially misled him; Ohm observed a magnetic needle's deflection and interpreted it as a measure of current.

Nothing can be tied securely to 1 May itself. After the book appeared that month it drew little institutional recognition, and hostile and reserved reviews followed in 1828.

Sources

Researched 23 Aug 2026 6 sources 2 audit passes Date disputed

How this was checked

Researched from the web into a fact sheet, rewritten from that sheet, then audited against it by a different model. How the pipeline works →

Date disputed. Sources disagree; the research places it at 1827-05.

What the sources leave uncertain

The exact date 1 May is securely attested as the date and place beneath Ohm's preface.
Catalogs generally give only 1827, while Deutsche Biographie says the book appeared in May. No consulted bibliographic source independently identifies 1 May as the publication or sale date.
Accordingly, 1827-05 is the best-supported publication date; treating 1 May as publication day is an inference from the preface.