Muñoz del Castillo’s physical units, fi rst book on dimensional analysis in history.

Abstract

«No book has been devoted to the dimensional analysis until 1922 –a hundred years after the appearance of Fourier’s Traité – as P.W. Bridgman published the course he taught at Yale University.» This is what Monod-Herzen (1976, p. 25) affi rms. Between both books, Fourier’s 1822 and Bridgman’s 1922, James Clerk Maxwell paved the way for the consolidation of this discipline, and his seed did not fall on barren ground. In Spain, without going any further, the work of Maxwell root from soon. So much history belies the French epistemologist. Yes, there is a book on dimensional analysis between Fourier and Bridgman. It is Physical Units written by the Spanish physicist José Muñoz del Castillo, who published it in 1890, that is thirty-two years before the publication of the book by Bridgman. Physical Units thus becomes the fi rst treatise devoted to dimensional analysis. Naturally I will not question that Bridgman’s Dimensional Analysis has been the fi rst complete treatise on this discipline. But it is not the fi rst book in which the theory of dimensions is presented, as it could be known in the nineteenth century, twenty four years before the proposal by Buckingham of his famous theorem pi. The purpose of this article is to highlight the acceptance and development of dimensional analysis in Spain in the 19th century, a circumstance so far not suffi ciently appreciated by the specialized historiography.