 Darrigol (2003), Biagioli (2016), Paula Cantù (2018), and Matthias Neuber (Neuber 2018a, Neuber 2018b) delve into Helmholtz’s work on the theory of measurement, including his essay “Über Zählen und Messen,” as a precursor of more recent treatments of the topic. Cantù focuses on the question of the applicability of mathematics in general, a question also found in Frege, Hale, Wright, and Batitsky, while Neuber and Biagioli focus on Helmholtz’s account of the a priori and empirical conditions for measurement in physics and mathematics. 