A very early student project undertaken by Friedrich Hegelmaier (1833-1906), published in German in 1852, is republished in English translation. Slight though the experimental work is, it nevertheless occupies a unique place in the history of experimental psychology. It is the source whence Fechner had the method of constant stimuli, a method that continued in use as the preferred psychophysical method, substantially in the form described here, for more than a century. The experiment is arguably the first experiment in the modern sense of a systematic preplanned body of observations and has the glaring faults that one would expect in a very first experiment. Finally, Hegelmaier suggests the use of two simultaneous tasks as a means to investigate human performance, a full hundred years before that idea was realized in practice. If only he had continued in experimental psychology!