Lehrbuch der Probier- und Hüttenkunde : als Leitfaden für akademische Vorlesungen
A German textbook on assaying and metallurgy by Alois Wehrle, published in 1841 by C. Gerold as a guide for university lectures, aimed at students of mining and smelting. Its plates are dense technical engraving of furnaces, flues, and crucibles shown in plan, elevation, and cutaway, with lettered keys and figure numbers. A designer could draw on their clean measured linework and hatching for industrial diagrams, schematic architecture, or vintage technical infographics.
