Osservazioni Intorno al Bosforo Tracio Overo Canale di Constantinopoli Rappresentate in Lettera Alla Sacra Real Maestá Cristina Regina di Svezia da Luigi Ferdinando Marsilii, 1681: First English Translation, with Notes

Count Luigi Ferdinando Marsigli (1658-1730) was a natural scientist and soldier of remarkable and idiosyncratic accomplishment. His first book reported observations and experiments that he carried out during and shortly after his one-year visit to Istanbul during 1679 and 1680. This work is recognized by oceanographers because it contains the first description of a simple laboratory-scale hydrological experiment to show how differences in the density of two water masses lead to two-layer flow. The range of observations and experiments that Marsigli made during that year, however, went well beyond this experiment, and are poorly known: he measured currents using the first example of a paddle-wheel current meter; he determined the water density in the Mediterranean and Black Sea; he estimated the depth of the Bosporus undercurrent; he made detailed meteorological observations and described the effect of weather on current and water levels; he described seasonal migrations of fish to and from the Black Sea, and illustrated the internal anatomy of a mollusk. We present here a complete English translation of Observations and set Marsigli's results in their historical as well as the modern context of the oceanography of the Bosporus region.