In the spring of 1848 (March Revolution), Hirsch, as president of the "Democratic Student Association" in Heidelberg, was committed to the radical ideas of introducing a republic in the Grand Duchy of Baden.

The following year, the General Conference of the Central European Arc Measurement, meeting in Berlin, voted a motion in ten articles laying the foundations of the international organization of the metric system, and thus prepared the work which ended on 20 May 1875 with the signing of the Convention of Metre.

Throughout the preparatory period Hirsch showed such great activity, such a clear-sighted mind, and identified himself so well with the common work, that he was, by a unanimous vote, chosen as secretary of the new committee in charge of high management of the International Bureau of Weights and Measures.

At the same time, the International Geodetic Association was born of the Commission of the Central European Arc Measurement, and, by an understanding the good effects of which were subsequently recognized, it was believed that the two new organizations, which creation had been almost parallel, would benefit from being run by the same men.

[5][6] The work of the two Associations is well known: the International Bureau of Weights and Measures, in its twenty-five first years of activity, has ensured the precise unification of the metric system in all civilized countries; The Geodesic Association caused great works, coordinated scattered measurements, made them stand out from each other, and finally, gave us a more perfect knowledge of the shape and dimensions of our globe, of the distribution of the gravity, seas' and continents' level, at the same time that it provided, to all the staffs, the solid bases on which the charts were built.