After obtaining a degree from the University of Cambridge Bose returned to India.
Henry Fawcett had given Bose an introduction to
Lord Ripon, the
Viceroy of India, who recommended him for a post to the Director of Public Instruction in Kolkata. In those days such posts in the Imperial Education Service were usually reserved for Europeans. Bose was appointed as an officiating professor of physics at
Presidency College. Although the principal
Charles Henry Tawney and Director of Education
Alfred Woodley Croft were reluctant to appoint him, Bose took up his post in January 1885. At that time, an Indian professor was paid two thirds the salary of a European and since his appointment was considered temporary, his salary was further halved, making his salary one-third that of his European peers. As a protest, Bose did not accept his salary and worked without remuneration for the first three years at Presidency College. He was popular among the students for his teaching style and demonstration of experiments. He got rid of the roll call. After three years in this temporary post, the value of his professorial work was recognized by Tawney and Croft, who made Bose's appointment permanent with retrospective effect. Bose received his full pay for the last three years in a lump sum. However, another source states that his appointment was made permanent on 21 September 1903, some 8 years after his joining the college. Bose used his own money to fund his research projects as well as receiving funding and support from the social activist nun
Sister Nivedita.
Microwave radio research crystal detector inside a horn antenna and galvanometer to detect microwaves. Bose invented the crystal radio detector,
waveguide,
horn antenna, and other apparatus used at microwave frequencies. Bose became interested in radio following the 1894 publication of British physicist
Oliver Lodge's demonstrations on how to transmit and detect radio waves. He began his own research in the new field in November 1894, setting up his equipment in small 20 ft sq room at Presidency College. The paper described Bose's plans for a
coherer, a term coined by Lodge referring to
radio wave receivers, which he intended to "perfect" but never patented. The paper was well received by
The Electrician and
The Englishman, which in January 1896 (commenting on how this new type of wall and fog penetrating "invisible light" could be used in
lighthouses) wrote: Wanting to meet other scientists in Europe, Bose was given a six month scientific deputation in 1896. Bose went to London on a lecture tour and met Italian inventor
Guglielmo Marconi, who had been developing a radio wave
wireless telegraphy system for over a year and was trying to market it to the British post service. He was also congratulated by
William Thomson, 1st Baron Kelvin and received an honorary Doctor of Science ( DSc) from the University of London. In 1900, he presented his research at the first
International Congress of Physics in Paris.
Place in radio development Bose's work in radio microwave optics was specifically directed towards studying the nature of the phenomenon and was not an attempt to develop radio into a communication medium. His experiments took place during the same period (from late 1894 on) when Marconi was making breakthroughs on a radio system specifically designed for wireless telegraphy and others were finding practical applications for radio waves, such as Russian physicist
Alexander Stepanovich Popov's radio wave based lightning detector, also inspired by Lodge's experiment. Bose was not interested in patenting his work, and openly revealed the operation of his galena crystal detector in his lectures. A friend in the US persuaded him to take out a US patent on his detector, but he did not actively pursue it and allowed it to lapse. pioneered the study of
chiral media, and preceded the fields of
artificial dielectrics and
metamaterials by decades and a century, respectively.
Development of the Mercury Coherer Detector Sir Jagadish Chandra Bose developed the self-recovering mercury coherer, a pioneering solid-state diode detector, which significantly advanced early wireless telegraphy. On 27 April 1899, Bose presented a paper to the
Royal Society describing an iron-mercury-iron or iron-mercury-carbon contact device, later recognized as the first patented solid-state diode detector (British Patent No. 7555, 1901; U.S. Patent 755840, 1904). This apparatus, capable of detecting radio signals without mechanical decohering, was integral to
Guglielmo Marconi’s transatlantic wireless transmission on 12 December 1901, which successfully received the
Morse code letter "S" at
Signal Hill,
St. John's, Newfoundland. In mid-1901, Marconi obtained a modified version of Bose’s detector from Lieutenant Luigi Solari of the
Royal Italian Navy. Solari’s adaptation encased a mercury droplet between carbon or iron electrodes within a glass tube. Marconi filed a British patent (No. 18105, September 1901), subsequently amended to acknowledge Solari’s contribution. The use of this device led to the "Italian Navy Coherer" controversy when Professor Angelo Banti, editor of
L’Elettricista, claimed in May 1902 that naval signalman Paolo Castelli was its inventor. This assertion prompted debates in British publications, including
The Electrician and
Saturday Review. Solari countered that his design drew from English scientific literature, likely referencing Bose’s 1899 paper. In 1903, Emilio Guarini attributed priority to Professor Tommaso Tommasina of
Genoa, citing his 1899–1900 experiments with mercury-based coherers. Marconi’s lecture at the
Royal Institution on 13 June 1902 distinguished Tommasina’s work from the detector used, and Solari confirmed he was unaware of Tommasina’s research until after the lecture. A detailed examination by Probir K. Bondyopadhyay, published by the
Institute of Electrical and Electronics Engineers (IEEE), clarifies the historical and technical significance of Bose’s contribution to the development of wireless communication.
Plant research Bose conducted most of his studies in plant research on
Mimosa pudica and
Desmodium gyrans plants. His major contribution in the field of biophysics was the demonstration of the electrical nature of the conduction of various stimuli (e.g., wounds, chemical agents) in plants, which were earlier thought to be of a chemical nature. In order to understand the
heliotropic movements of plants (the movement of a plant towards a light source), Bose invented a torsional recorder. He found that light applied to one side of the sunflower caused turgor to increase on the opposite side. He was also the first to study the action of microwaves in plant tissues and corresponding changes in the cell membrane potential. He researched the mechanism of the seasonal effect on plants, the effect of chemical inhibitors on plant stimuli and the effect of temperature.
Study of metal fatigue and cell response Bose performed a comparative study of the fatigue response of various metals and organic tissue in plants. He subjected metals to a combination of mechanical, thermal, chemical, and electrical stimuli and noted the similarities between metals and cells. Bose's experiments demonstrated a cyclical fatigue response in both stimulated cells and metals, as well as a distinctive cyclical fatigue and recovery response across multiple types of stimuli in both living cells and metals. Bose documented a characteristic electrical response curve of plant cells to electrical stimulus, as well as the decrease and eventual absence of this response in plants treated with anaesthetics or poison. The response was also absent in metal treated with
oxalic acid. == Science fiction ==