Radhanath was the eldest of two sons and three daughters born to TituramSikdar of Jorasanko, Calcutta (now Kolkata). The family that had once enjoyed power and prestige had fallen on hard times. Radhanath was known for his sturdy physique, fearless nature and a surprisingly open mind. He did not hesitate to take to task young British lads who were rude to the women of his neighbourhood. Radhanath’s father ensured that his sons received proper education that would enable them to get good jobs. Radhanath received his primary education initially in a village pathsalaand later at the school called firangi Kamal Basu’s school because Kamal Basu was a convert to Christianity. At age thirteen Radhanath entered of the Hindu College, Calcutta (now Presidency University, Kolkata) where his life was transformed by the fiery social reformer Henry Vivian Derozio. As an enlightened Derozian, he was opposed to child marriage and refused to marry the eight- year-old girl his mother had chosen for him. Radhanath was known to be devoted to his mother and it is believed that he never entered into marriage because he wanted to atone for having disagreed with his mother.
Both Radhanath and Srinath received scholarships. Radhanath was awarded a scholarship of Rs.16 in the First Class. He used most of the money to buy books while Srinath’s scholarship was used to sustain the family. Recognising that Radhanath was a
maths wizard and a child prodigy, Dr. John Tyler, his mathematics tutor, took him under his wings. He introduced Radhanath to Newton’s Principia Mathematica and thus catalysed his interest in physics. Radhanath gained mastery over English, Sanskrit, and Philosophy as well. He also learnt some Greek and Latin. He studied Euclid’s Elements, Windhouse’sAnalytical Geometry and Astronomy, Lagrange’s Theorem, and Jephson’s Fluxion−seminal works that consolidated his hold over the subject. While still a student, he published a new method for drawing common tangent to two circles in Gleanings in Science (Vol. III, 1831). The Editor commented, “The solution is altogether his own discovery, and I have not altered a word in his composition.”
However, although a brilliant student, Radhanath did not complete his studies. After spending seven years and ten months in Hindu College, he joined the ‘Great Trigonometric Survey of India’ (GTS) on 19 December 1831 at an initial salary of Rs. 40. His name had been suggested by Dr. Tyler and he was the first Indian to join the Survey; a herculean attempt to carry out geodetic survey of India. However, it became clear that his mathematical abilities far outstripped those of his colleagues. He was soon appointed as Sub-assistant to GTS. In 1832 he joined the then Surveyor General, Sir George Everest to begin work in the Dehradun region. Radhanath was promoted to the post of Chief Computer in Survey of India in1851. The term “computer” in the context of a post may seem odd now, but in those days it merely meant that the person was computing numbers. RadhanathSikdar served as one of the land surveyors in the Dehradun circle for 20 years.
Andrew Waugh, who succeeded Sir George Everest as Surveyor General in 1843, asked Radhanath to devise a formula for calculating the heights of the peaks of the Himalaya. From a distance of 150 miles (about 242 km), Radhanath collected necessary data for his work from six different locations. He realised that atmospheric refraction affected the readings and developed methods for making the necessary corrections. However, it was not till 1856 that Peak XV was announced as “most probably” the highest mountain in the world with a height of 29,002 feet (8,840 metres). In 1865, Peak XV was finally named Mount Everest by the Royal Geographical Society upon a recommendation by Andrew Waugh.
By then, RadhanathSikdar had been transferred to Kolkata. So, in 1851, in addition to his service to GTS, he took up responsibilities as the Superintendent of the Meteorological Department. He introduced many novel innovations that stood the test of time for decades. He had realised that the thermal expansion of the metallic scale attached to the barometer, as well as the dilation of the mercury inside the instrument, affected barometric readings. So he devised a formula for conversion of barometric readings taken at different temperatures to 32 degrees Fahrenheit (0 degree Celsius). The formulae used in Europe were unknown to him. Undeterred, he devised these formulae on his own. His research paper was published in the Journal of Asiatic Society of Bengal in 1852, wherein he presented his formula. As a mark of recognition of his mathematical ability, he was elected a member of Bavarian branch of the famous ‘Philosophical Society’ of Germany. He was the first Indian to achieve this honour.
RadhanathSikdar retired from active service in 1862. Subsequently, he became involved in various philanthropic activities. With his friend Peary Chand Mitra (1814- 1883) he jointly edited a monthly magazine (masikpatrika) meant primarily for women. Thus, he may have been one of the early pioneers of popular science writing. In the closing years of his life, Radhanath worked as a mathematics teacher at the General Assembly Institution, (now, Scottish Church College), Kolkata.
RadhanathSikdar passed away on 17 May 1870 in Chandannagore town, West Bengal; where his grave may still be seen. The unkindest cut came after he passed away. RadhanathSikdar’s contribution to the preparation of the Manual of Surveying for India (Eds. Capt. H. L. Thullier and Capt. F. Smyth) had been duly acknowledged in the preface to the first and second editions. However, this acknowledgement was omitted in the third edition that came out in September 1875. The colonial rulers had decided to delete the name of a deceased native from the publication; they knew the dead man could not protest. This did not go un-noticed by the media. In 1876, the paper Friend of India called it, “robbery of the dead”.
In the obituary published in the Hindu Patriot he was described as: “…a remarkable man … many good qualities.” The Department of Posts, Government of India, issued a postal stamp on 27 June 2004, commemorating the establishment of the Great Trigonometric Survey in Chennai. The stamp features RadhanathSikdar and Nain Singh, two significant contributors. A tablet has been erected in the National Library, Kolkata in memory of RadhanathSikdar.
Sikdar’s achievements cannot be understood unless one realises the tremendous hurdles he overcame with such apparent ease. India in the early nineteenth century was not an easy country to traverse carrying large yet sensitive equipment. It has been calculated that the average length of a side of the triangulation was almost 50 km, the maximum being almost 100km. The instruments were huge and cumbersome too. Imagine trying to establish a clear line of sight in densely forested regions where attacks from wild animals could not be ruled out; or fording raging rivers carrying the instruments. Yet Radhanath did all this and more. Faced with the need to devise formulae for accurate readings, he drew on his expertise to meet the intellectual challenges. In an age when India was an enslaved nation, RadhanathSikdar did not just discipline the unruly British elements but also stood shoulder to shoulder with the British scientists and forced them to acknowledge him as their peer.