Planted across West Bengal and Jharkhand are several masonry towers about two hundred years old. The hollow structures are usually four- or two-storied. The latter are found atop hills in the Purulia district or in parts of Jharkhand, while the four-storied towers stand tall in open fields, crowded streets or deep inside remote jungles. Often indentified as watch towers, these are semaphore signal towers — key to the optical telegraph lines set up by the British between 1816 and 1830. The lines were part of a long-distance communication system based on towers with shutters or moving wooden arms using semaphore signals. The longest semaphore line in India was four-hundred-miles long, stretching from Calcutta to Chunar. On a clear day, news reached from Fort William, a British outpost in the capital of the Bengal Presidency, to Chunar in fifty odd minutes.
Optical telegraphy originated in France in the late eighteenth-century. In 1816, the British decided to use it in India on an experimental basis, mainly to send military information. The survey was conducted by George Everest and planned by William Boyce. The towers were built by people across several locations. However, the rising cost of maintenance and the advent of electrical telegraph (telegram) eventually sounded the death knell for the semaphore telegraph in India. The Calcutta-Chunar line operated only till 1828, while short-distance lines such as the ones from Calcutta to Khejuri were functional till the 1840s. With the last telegram sent out a month ago, the age of the telegraph has come to a grinding halt. It’ll be a pity though, if its predecessor, the semaphore telegraph’s towers go to seed and an important chapter in the history of communication is lost forever.