This paper discusses two methodological notions, the concepts Gegenprobe (countercheck) and Gegenversuch (counter-trial), which were widely applied, discussed, relied upon, and defended in German-language writings about empirical inquiry. In the decades around 1800, they were common in physiology; medicine; agriculture; chemistry; various technologies, such as printing, metallurgy, and mining; accounting; and legal and political argumentation. The ubiquity of those concepts signals a broad concern with securing empirical findings and empirical knowledge. Gegenproben and Gegenversuche – the terms as well as the (...) practices – are evidence for the close connection among explicitly knowledge-seeking endeavors and crafts and technologies. Physiological experiments, chemical analyses, agricultural or vaccination trials were indebted to applied and practical procedures of making and assaying. What united these different fields was the fact that the problems that had to be solved were very complex yet at the same time of immediate relevance to everyday lives (like diseases or crops) or highly controversial (like vital forces or spontaneous generation). We know that late eighteenth-century and early nineteenth-century practices of inquiry were firmly embedded in applied, technical contexts; this essay shows that methodological notions were anchored in applied, technical contexts as well. (shrink)