: In 1842, British astronomer Sir John Herschel wrote a letter to Carl Friedrich Gauss seeking his advice about how to make data collection more efficient on the Magnetic Crusade, a large-scale initiative to study the earth's magnetic field. Surprisingly, even though Gauss had managed a similar initiative, he refused to give Herschel the advice he wanted, claiming that he needed to see Herschel's results before he could reply. Taking this miscommunication as a point of departure, this article traces the (...) cause of this miscommunication to differences in how each scientist viewed scientific training and the communicability of different kinds of scientific knowledge. (shrink)