1856 Physical Chart of the Indian Ocean

This is Johnston's Physical Chart of the Indian Ocean. It was published in the second edition of Johnston's Physical Atlas of Natural Phenomena, out of Edinburgh by William Blackwood & Sons in 1856. The chart contains a remarkable amount of information including temperature of the water, currents of the air and ocean, direction of the wind, districts of hurricanes, regions of monsoons and typhoons, trade routes and more. It includes explanatory notes for the markings used, and a legend for its colour coding. At the time of publication, Alexander Keith Johnston's Physical Atlas of Natural Phenomena was amongst the most comprehensive geographic works of its day to  focus on natural science. Johnston described the motivations and focus of his work in the preface as follows; The object originally contemplated in this work was to present, in a graphic form, a concise yet comprehensive view of the Physical Geography of the Globe, embracing under that term its superficial structure, the m