In 1850, the Chief Physical Observatory began collaborating with the Hydrology Department of the Russian Navy, primarily in the organization of the meteorological service in the seas. By the mid-1890s the number of marine meteorological stations exceeded 100, more than 80 of which were financed by the Navy. Such long lasting collaboration relied on consistent efforts on both sides: the commanders and officers of the Hydrolo gy department, including A. G. Villamov, S. I. Zelenoi, N. N. Treskovsky, M. A. Rykachev, E. V. Maidel, and academicians and scientists at the Physical Observatory-A. Ya. Kupfer, G. I. Vild, and others.