This fantastically detailed and accurate sea chart represents the first truly scientific maritime map of Bombay Harbour. Taken from a westward perspective, the many shoals, rocks and maritime hazards, as well as navigational aids are clearly marked, while innumerable bathymetric soundings quantify the sea floor. The fort and town of Bombay occupy the southern tip of the island to the centre-right of the chart, while a fine profile view can be seen above. While Bombay possessed an excellent natural harbour and was India’s busiest port, its entrance was considered treacherous. While previous charts were useful, Horsburgh’s was the first that, if correctly followed, would guarantee safe passage. James Horsburgh was a Scottish sea chart maker who played a revolutionary role in the scientific mapping of the coastal waters of India and Southeast Asia. He spent 27 years sailing about Asia, often based out of Bombay. In 1786 Horsburgh was shipwrecked on the island of Diego Garcia in the Indian Ocean, due to the errors on the best available sea charts. This traumatic experience inspired him to dedicate the rest of his life to the accurate mapping of Asian waters. Horsburgh realized that the best available chart of the Bombay Harbour, an updated version of William Nicholson’s 1763 chart, was not sufficiently detailed. In 1803-4, Horsburgh used the most advanced equipment and techniques of triangulated surveying to precisely map the entrance to Bombay Harbour. The resulting chart, printed in 1806, prevented innumerable accidents, saving countless ships and lives. In 1805 Horsburgh moved to London where he became a leading sea chart publisher. His charts helped to set the new ‘gold standard’ for the mapping of Indian and Asian waters. In 1810, he was appointed as the official Hydrographer of East India Company, a post he held for the next 26 years.