In 1870 Petermann advocated the use of a red and blue color scheme for temperature maps of the oceans. Although the number of projection methods increased at a reasonable rate, a few well-known sorts, like the stereographic and orthographic equatorial projections and the projections of Lambert, Flamsteed and Mercator, remained the most popular. Petermann did publish reports on the new projection methods of J. Babinet (1854) and J. James (1857), and G. Jäger, but he hardly used them. Though Petermann and Ernst Behm (1830–1884; like many of the famous Gothaer geographers and cartographers Behm had first another profession. He was a physician, who learned the geographic trade in practice) wrote many articles about geodesy and surveying, they rarely got involved in other technical and theoretical cartographic issues.