Radhanath Sikdar

Radhanath Sikdar was born in 1813 in Jorasanko, a neighborhood in north Kolkata (then Calcutta), into a Bengali Hindu family of modest means ^[1]. His father, Tituram Sikdar, could offer his son little wealth, but the boy grew up in a city that was becoming the intellectual center of British India, where new schools were opening English education to Indian students for the first time.

After early schooling at a local institution, Sikdar entered Hindu College (the forerunner of Presidency University) in 1824, at about eleven years of age ^[1]. The college was then the crucible of a generation. Henry Louis Vivian Derozio taught there until 1831, and his freethinking students became known as Young Bengal, a circle that questioned orthodox custom and embraced rational inquiry. Sikdar absorbed that spirit and kept it for the rest of his life ^[2].

His real gift, though, was mathematics. Under John Tytler, who taught the subject at Hindu College, Sikdar advanced far beyond the standard curriculum, working through Newton's Principia and studying analytical geometry and advanced calculus at a time when very few Indians had access to European higher mathematics ^[1]. By his late teens he was reported to be one of only a handful of people in India, of any nationality, comfortable with the spherical trigonometry that geodesy demanded. That skill would decide the course of his life.

In December 1831 the Great Trigonometrical Survey of India, the vast project to measure the subcontinent with mathematical precision, needed calculating staff. Tytler recommended his nineteen-year-old student, and Sikdar joined the Survey as a "computer", the era's term for a human calculator, on a salary of thirty rupees a month ^[3]. The Survey was then completing the Great Arc, a chain of triangulations running up the length of India, one of the most ambitious scientific measurements ever attempted ^[4].

Sikdar was posted to Sironj in central India and worked directly under Sir George Everest, the Surveyor General whose name the world's highest peak would later carry. Everest quickly recognized the young Bengali's ability. Surviving Survey correspondence shows Everest rating him among the most valuable members of his establishment, and when Sikdar considered leaving for a better-paid post elsewhere, Everest intervened to keep him ^[3]. Fieldwork in the Survey was punishing: computers reduced thousands of observations by hand, correcting for refraction, curvature, and instrument error, with no margin for mistakes.

Sikdar did more than calculate. He devised improved procedures for the everyday geodetic problems the Survey faced, and several of his methods were adopted into its working manuals ^[2]. When Andrew Scott Waugh succeeded Everest as Surveyor General in 1843, Sikdar's standing continued to rise. In 1851 he was transferred to Calcutta and promoted to Chief Computer, taking charge of the Survey's calculating office, and he simultaneously superintended the meteorological department at a combined salary that made him one of the highest paid Indians in British scientific service ^[1].

The achievement that anchors any account of Radhanath Sikdar achievements came from data he never gathered himself. Because Nepal was closed to the Survey, observers measured Himalayan peaks from stations in the Indian plains, well over a hundred miles away. Between 1849 and 1850 field parties recorded theodolite readings of a distant summit catalogued simply as Peak XV ^[4].

Reducing those observations was ferociously difficult. Light bends as it passes through the atmosphere, so every vertical angle had to be corrected for refraction across enormous distances, along with corrections for the curvature of the Earth and the gravitational deflection caused by the mountains' own mass. This work fell to the Chief Computer's office in Calcutta under Sikdar's direction. By tradition, in 1852 Sikdar completed the computation and reported to Waugh that Peak XV was the highest mountain yet measured on Earth ^[3][4]. The height eventually announced in 1856 was 29,002 feet, remarkably close to the modern figure of about 29,032 feet.

Waugh named the peak after his predecessor George Everest, over Everest's own objections, since Survey policy preferred local names where they could be learned ^[4]. Sikdar's exact share of the discovery has been debated by historians, because the reduction of the Himalayan observations was the collective work of his office over several years. What is not in dispute is that he headed the computing establishment responsible for the result, and colonial-era accounts of the Survey themselves credited the Bengali Chief Computer with the calculation ^[3]. Among Radhanath Sikdar facts, this remains the best remembered: the height of Everest was first fixed not by a climber but by a mathematician at a desk in Calcutta.

Sikdar carried the Young Bengal temperament into adult life. As a young man he refused a marriage his family had arranged, reportedly because he objected to child marriage, and he never married at all, an almost scandalous choice in nineteenth-century Bengali society ^[2]. He was physically vigorous, fond of long walks and exercise, and friends recalled his blunt, independent manner.

That independence cost him. While serving in the field at Dehradun, Sikdar confronted a British magistrate named Vansittart over the illegal impressment of Survey laborers, who were being forced to carry loads without proper pay. He lodged a formal protest, and for his defiance he was prosecuted and fined 200 rupees ^[2]. The episode became well known in Bengal as an early instance of an Indian official standing up to colonial abuse of power on behalf of ordinary workers.

He felt the sting of colonial inequity in his own career as well. In 1851 Sikdar and his colleague Captain Henry Thuillier prepared the Survey's technical handbook, and Sikdar wrote a substantial part of its mathematical content. In a later edition published after his death, his name was removed from the title material, an erasure that the Anglo-Indian newspaper The Friend of India openly condemned at the time as an act of injustice toward a dead man who could not defend himself ^[1][5].

From his Calcutta office Sikdar broadened his work beyond geodesy. As superintendent of the meteorological observatory he standardized the reduction of weather observations and devised a simplified method for converting barometric readings to sea level values, work that circulated in scientific publications of the day ^[1]. His reputation traveled: the German Philosophical Society of Leipzig elected him a corresponding member, a rare honor for an Indian scientist of that generation ^[2].

He also turned to the cause that animated many Young Bengal veterans, the spread of knowledge in the Bengali language. In 1854, together with the writer Peary Chand Mitra, Sikdar founded the monthly journal Masik Patrika, aimed particularly at women readers and written in plain, direct Bengali rather than the ornate literary style then standard ^[2][6]. The journal carried essays on science, social questions, and everyday subjects, and it is remembered as a landmark in Bengali prose and in early efforts at women's education.

Sikdar retired from the Survey in 1862 after three decades of service. In retirement he taught mathematics at the General Assembly's Institution (later Scottish Church College) in Calcutta and continued his intellectual pursuits ^[1]. He died on May 17, 1870, at Chandannagar, the French enclave on the Hooghly north of Calcutta, at the age of about fifty-seven ^[1].

For decades after his death Sikdar was a half-forgotten figure outside Bengal, his contribution folded anonymously into the institutional record of the Survey of India. Interest revived in the twentieth century as Indian historians of science reconstructed his career from Survey archives and contemporary Bengali sources, and any modern Radhanath Sikdar biography now treats him as a founding figure of Indian participation in modern exact science ^[2].

Formal recognition followed. In June 2004, on the anniversary of the public announcement of Everest's height, the Department of Posts of India issued a commemorative stamp honoring Sikdar and the Survey's pioneering computers ^[6]. The Survey of India itself has acknowledged his role in its own historical publications, and his name appears regularly in accounts of the Great Arc, including John Keay's widely read history of the project ^[4].

His legacy runs in two channels. In science, he demonstrated in the 1830s and 1840s that Indians could work at the highest level of contemporary mathematics, decades before Indian universities produced their own research traditions. In public life, his protest at Dehradun, his refusal of orthodox marriage customs, and his Bengali journal made him a small but genuine force in the social reform currents of nineteenth-century Bengal ^[2][6]. The mountain he measured bears an Englishman's name, but the calculation that revealed its supremacy is inseparable from his.