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Jagadish Chandra Bose (1858-1937)
Born
30/11/1858 Faridpur, India (now Bangladesh) The father of wireless communications! And his name was Jag! Nearly 100 years after Guglielmo Marconi's first transatlantic wireless communication, it has come to light that the detector he had used to pick up the signal was invented by Professor Jagadish Chandra Bose. The discovery made by a group of scientists of the US-based IEEE proves what has been a century-old suspicion in the world scientific community: that the honour of being the pioneer in wireless communication should have gone to Bose and not Marconi. Bose's invention of the mercury coherer with a telephone, which Marconi used, was published in the Proceedings of the Royal Society, London, on April 27, 1899, over two years before Marconi's first wireless communication on December 12, 1901, from Newfoundland, now in Canada. In January 1998, the IEEE published a special issue, where evidence was presented to show that Marconi had used the sensitive semiconductor diode device invented by Bose. Investigations by the IEEE group show that both Bose and Marconi were in London in 1896-97. The Italian was conducting wireless experiments for the British post office and Bose was on a lecture tour. Both scientists were interviewed by McClure's Magazine (now defunct) in March 1897. In the interview, Bose came out with high praise for Marconi, then under attack from established British scientists who doubted his credentials. Marconi never could make it to college because of his poor high school record. Bose also said he was not interested in commercial telegraphy and that others could use his research work. In 1899, Bose unveiled his invention of the mercury coherer with the telephone detector in a paper at the Royal Society. In a curious coincidence, Bose lost his diary containing an account of the invention and a prototype of the detector during a lecture tour in the same year. Brilliant Marconi quickly grasped the commercial importance of Bose's invention and began to explore it secretly. His childhood friend Luigi Solari started experimenting with Bose's invention and presented Marconi with a slightly modified design in the summer of 1901 for use in the upcoming transatlantic experiment. The Italian scientist then went on to apply for a British patent in his name, never acknowledging his debt to Bose. Securing Bose's place in the history of long-distance communication, the IEEE paper narrates how the truth was suppressed all these years, even though it was there for all to see in the 1899 Proceedings of the Royal Society. A combination of factors like naivete about patenting, plain misfortune and politics of the contemporary times weighed against Bose. Bio by Sreemathi Hariprasad Jagadishchandra Bose was born on the 30th of November 1858 in Faridpur in Dacca District. Faridpur was a part of India until 1947; now it is in Bangladesh. His mother Abala Bose was a tenderhearted and affectionate woman. His father Bhagawanchandra Bose was a man of excellent qualities. Bhagawanchandra Bose was the Deputy Magistrate of Faridpur. He helped very generally the poor and the needy. He would comfort people in sorrow. There was a famine in Bengal in the year 1880. Bhagawanchandra Bose spent his own money to help the poor villagers. In the year 1874 hundreds of families suffered because of widespread malaria. Thousands of children lost their parents and became orphans. Bhagawanchandra Bose helped these orphans. He spent money from his pocket to start a factory and provided had to spend a lot of money on these. But he never regretted doing so. In the days of Jagadishchandra Bose’s boyhood, the well educated and the well to do people were attracted by Western culture. A man was proud if he had learnt English. But Jagadishchandra Bose’s education was really remarkable; it was due to his father. As long back as a hundred years ago, Bhagawanchandra Bose started schools in which children were taught in Bengali. Jagadishchandra also received his early education in this school. Jagadish mixed with the poor boys freely and played with them; so he gained first hand knowledge of the sufferings of poor people. He learnt much more. He learnt how the fisher folk moved on the broad rivers in their boats, how the fishing rod was cast in the flowing water, how ploughing the land and sowing seeds in it grew the crops and how the cattle were taken to graze on the distant hills. He was all ears when the fishermen and the farmers gave such accounts. He was thrilled by their adventurous life and it made him more courageous in life. There was another interesting person in his early life. This was a servant who used to take Jagadishchandra to school every day. He had been a dacoit in the past Bhagawanchandra Bose as a judge had sent him to prison. After some time the dacoit came out of prison. But how was he to live? Bhagawanchandra Bose was a very good-natured man. So he employed him as a servant. The dacoit used to tell little Jagadishchandra. events of his past life the robberies he had committed and his cruel deeds. His adventures made a lasting impression on the boy. Young Bose was all curiosity. He wanted to know about everything that happened around him. What is a glow-worm? Is it fire or spark? Why does the wind blow? Why does the water flow? He was always ready with a string of questions. His father would answer as many questions as he could. But he never tried to impress upon his son that he knew everything. If he could not answer a question, he would frankly tell his son so. Thus Jagadishchandra's parents took great interest not only in his studies but also in everything that shaped his character. They narrated stories from the Ramayana and the Mahabharatha to him. Karna of Mahabharatha was an idoll to him. (Karna was a great hero but, more important still, very generous.) He went with his parents to see the performances of folk drama. (These were staged in open-air theatres.) They treated all his friends alike. Such was the environment for Jagadishchandra in his boyhood. He grew up to be broad-minded, patriotic, obedient to elders, affectionate towards his fellowmen. He never made any distinction between the rich and the poor; all men were equal in his eyes. Generally it is easy to understand a subject if it is taught in the student's language; it becomes difficult if it is taught in some other language. Jagadishchandra did not face this problem, since he studied the subjects in his own language. He understood them easily. He was in the habit of thinking for himself whenever he studied. He learnt many things on his own by studying at home. But he was not a bookworm. He was very enthusiastic about games too. Cricket was his favourite sport. Jagadishchandra began a new chapter in his life at the age of nine. He had to leave his hometown. He went to the big city of Calcutta for further education. He was admitted to Saint Xavier School there. There was a world of difference between the previous school and this one. In Faridpur he had studied everything in his own language. But here in Calcutta his schoolmates knew only English. The city boys, especially the English boys, teased him. One of them even hurt Jagadishchandra in a bout of boxing. Jagadish was provoked and he taught the boy a well- deserved lesson. That was the end of any teasing. While he was studying at Saint Xavier's, Jagadishchandra was staying in a boarding house. He had no friends and was lonely here. But he was a born scientist. Even as a boy he had many hobbles which showed his scientific interest. He used to breed frogs and fishes in a pond nearby. He would pull out a germinating plant and observe its root system. He had also a number of pets like rabbits, squirrels and non-poisonous snakes. Even in Calcutta he continued these hobbies to get over his solitude. He grew flower-bearing plants and had animals and birds as pets. He did well in his studies and was in the forefront. The teachers liked him for his intelligence. Jagadishchandra passed the School Final Examination in the First Class. He joined the B.A. class in the college. In those days, science subjects formed a part of this course. He was most interested in Biology (the science of life). But Father Lafont, a famous Professor of Physics, inspired in Bose a great interest in the science of Physics and Bose became his favourite student. Even so, Bose was always interested in any branch of science. Botany, the science of plants, still attracted him much. By nineteen, Jagadishchandra was a Bachelor of Arts. He wanted to go to England for higher studies. He wished to try his luck at the Indian Civil Service Examination or to study medicine. If he entered the Civil Service, he would be a government officer. This would mean subordination; his father did not want Jagadish to work under others. And he did not have enough money to send the boy abroad. Besides, he wanted that his son should become a teacher and serve his people and his country. Even Jagadishchandra's mother was not quite willing to send him, because she thought it was against their religion. She was pained at the thought that her son would be far away from her. Jagadishchandra Bose did not wish to do anything against the will of his parents. Finally, his good mother allowed him to go. She had saved some money. She also wanted to sell her jewels to meet the expenses of her son's voyage. Bhagawan chandra Bose prevented her and he managed to find the money on his own. At last Jagadish was on his way to England. The year was 1880. Twenty- two-year-old Jagadishchandra Bose stepped into the ship; he was stepping into a new phase of life which laid the foundations of a brilliant future. In London he first studied medicine. But he repeatedly fell ill. So he had to discontinue the course. He then studied Natural Science in Christ Church College, Cambridge. It was necessary to learn Latin in order to study Natural Science; Jagadish had already learnt it. He passed the Tripos Examination with distinction. In addition to the Cambridge Tripos Examination, he passed the Bachelor of Science Examination of London University also. Jagadishchandra Bose was back in India. He joined the staff of the Presidency College, Calcutta. There was a peculiar practice in that college. The Indian teachers in the college were paid one third of what the British teachers were paid! So Jagadishchandra Bose refused his salary but worked for three years. He could not even get the scientific instruments he needed for research. He was not shown the respect due to him. This did not continue for long. His deep knowledge zest for work and cultured behavior won over those in charge of the college. They saw to it that he was given the full salary of the post and not one-third. Teaching the same lessons year in and year out was very tedious to Bose. His was an alert mind, always on the look out for new ideas. He wanted to do research, to widen his knowledge and discover new things. A laboratory is necessary for research. Many scientific instruments are required. Jagadishchandra Bose had no laboratory and he did not have the instruments. But he was not disheartened. For eight or ten years he spent as little out of his salary as possible, lived a very strict life, saved money and bought a laboratory! Generally Marconi's name is associated with the invention of wireless. (This made possible the use of the radio.) Jagadishchandra Bose had also conducted independent research in the same field. Marconi was able to announce the result of his work and show how wireless telegraphy worked, earlier than Jagadishchandra Bose. So he is called 'the father of the radio'. In the year 1896 Bose wrote a research article on electro-magnetic waves. This impressed the Royal Society of England (which is famous all over the world). He was honoured with the Degree of Doctor of Science. He needed money to continue his work. Bengal, his homeland, came forward to bear the expenses. Those were days when the British Government would not help an Indian to go abroad for studies. Bose had the honour of getting encouragement even from the British Government. And he made excellent use of this. Bose became famous in the world of science. In India and in other countries there was a strong belief that only Westerners could achieve anything worthwhile in science. Bose proved this wrong concept. He showed that there were geniuses elsewhere too. He visited England again, this time to explain his discoveries to the scientists of the West. Bose needed scientific equipment. But the instruments he needed were not available. But this did not hamper his work. Early in his life he had learnt to make his equipment with his own hands. The scientific instruments he took to England were those he himself had made. Electricity was then his special field of work. He had successfully worked at transmitting electro-magnetic waves from one place to another. He had determined the type of instruments required both at the transmitting end and at the receiving end; he had found out what the distance should be between these two ends. He was using the instruments he had himself made. Bose demonstrated his discoveries at the Royal Society in England. The gathering of scientists were profoundly impressed. They praised this achievement as a singular one from a citizen of India. Our country was until then famous only as the home of philosophy and religion. Bose won respect for Indians in science too. The renowned papers of London namely 'The Spectator' and 'The Times' were all praise for this Indian scientist. For, without proper facilities and with the available material, Bose had achieved wonderful results and he had done his research along with his teaching work. After he lectured at the Royal Society, scientific associations in many other countries invited Jagadishchandra Bose. He visited France, Germany, America and Japan besides England. He lectured at several places and explained his discoveries. When electricity passes through a man, animal or plant, we say there is a 'shock'. When it is passed through a living being the being gets excited, 'irritated'. Bose developed an instrument that would show such a reaction of the organism on agraph. When electricity was passed through zinc, a non-living substance, a similar graph was obtained. So he came to the conclusion that living and non-living things were very similar in certain reactions. In Paris he gave a lecture on this similarity between the living and the non-living world. Have you heard of 'radar`? This is a very wonderful scientific device. Sailors on the sea use it; it is also used to get information about aeroplanes coming towards a place. So you see how useful it is during a war. If the aeroplanes of the enemy try to attack a city, the radar shows their movement. J.C. Bose worked out some details of very great importance; these are being used in the working of the radar. When Jagadish chandra Bose again visited England, Cambridge University honoured him as a Professor. Generally, when a man invents something new he declares that nobody can make use of it without his permission. If anybody desires to, make use of it, he will have to pay him money, Why? Because the inventor has worked hard and he has used his time and brains for his invention. It is not right to make use of his work without paying him. An inventor can make lakhs of rupees by just one or two inventions. Bose had invented many instruments. They have since been used by many industries. When he was offered money for these he did not accept it. He was very generous and noble; he felt that knowledge was not any one's personal property. He permitted any one the use of the fruits of his work. The Davy-Faraday Research Institute is a very famous scientific institute for scientific research in England. This institute requested Jagadishchandra Bose to continue his research there. Many eminent scientists pressed him to do so. Hence he worked there for some time and discovered new things. When an outside stimulus is applied to the muscles of a man or a non-living thing (says a mineral), they respond to it. Bose wondered whether this could happen in a plant also. To test this he brought a leaf, a carrot and a turnip from the garden. He applied the stimulus, i.e., and electricity. It was confirmed that plants also respond in a similar way. Jagadishchandra Bose explained this at a meeting of the Royal Society. While explaining his discoveries he said that the Indian sages had under stood such principles thousands of years ago. He modestly added that his discoveries were an insignificant part of the great truth that our ancient sages had realised. When anything new is discovered, there will always be people who question it. The results of Bose's work, too, were not accepted by all. There were people who challenged them and even said that there was not much truth in them. Bose gave a lecture at the Linnean Society next year to a gathering of scientists. He explained with suitable experiments how plants respond to stimuli. Even those who had challenged him could not find fault with his experiments or conclusions. There is an interesting story about a demonstration that Bose gave in England. On that day he wanted to show some new things that he had found out. He had come to the conclusion that plants can feel pain like animals; that when we pinch them they suffer; and that they die in a few minutes after they are poisoned. Bose wanted to show experiments to prove these conclusions. A number of scientists and other leading men and women had gathered to hear him. Bose started the experiments by injecting poison into a plant. The plant should have shown signs of death in a few minutes. On the contrary, nothing happened. The learned audience started laughing. Even at this adverse moment Bose showed admirable calmness. He thought quickly. The poison that he injected into the plant did not kill it. So, he supposed that it would not hurt him also. With full confidence he got ready to inject the poison into himself. At that instant a man got up and confessed that instead of poison he had put similar colored water. Now, Bose conducted the experiment again with real poison, whereupon the plant withered and died as expected. Jagadishchandra Bose continued his work and made new discoveries. He found that plants shrink a little during the night. He found out why plants always grow towards light even if they have to bend. He also found out the reason why some plants grow straight and some do not. He explained that this was due to the 'pulsation' in plants. This pulsation quickens by heat and slows down by cold in plants. Jagadishchandra Bose did remarkable work, and scientists outside India had honoured him. Yet there were people who opposed him. As a result even the Royal Society delayed publishing his valuable work in its publications, But nothing could make him give up his work. He was sure that years of research had led him to the truth. So he did not feel that it was very necessary to depend on scientific journals only. He wrote books and published them on his own. By this time Bose had made a name for himself as a great scientist. The instruments he had developed were being used in some Western countries too. He visited Europe and America in 1907 and 1914; scientific institutions invited him to explain his discoveries. He visited Japan also. Most of us have seen a peculiar kind of plant called the mimosa (touch-me-not') which spreads on the ground. It has very small leaves. It is extremely sensitive. If we just touch one leaf, that leaf and the leaves nearby all fold up. The greater the force we use, the larger the number of leaves which fold up. The whole row of leaves of the branch can be made to fold like this by touching it with a little greater force. Why does only this plant react like this? We have often wondered, haven't we? Bose wondered, too. And he went on to find out. He found that other plants also react to a man's touch in the same way. The only difference is this: We cannot see the reaction of other plants but we can see the reaction of the mimosa. But Bose wanted to study the reaction of other plants, too. He designed delicate instruments that would show such reactions in them. When he went abroad he took these instruments and also some of the plants with him. It was very difficult to keep the plants alive in the, climate of foreign countries. Jagadishchandra Bose showed the experiment in Cambridge and Oxford. The scientists were fascinated by the extreme sensitivity of plants; they were also filled with wonder when they saw the excellent instruments Jagadishchandra Bose himself had made. No one had done work of this kind in Biology. It was news that plants could also experience different sensations like us. Jagadishchandra Bose continued his search for new knowledge. His achievements were many. The British Government honoured him more than once. In 1915 when retired from service he was made an Emeritus Professor. He was to get Rs. 1500 a month as long as he lived. He was honoured as a Fellow of the Royal Society (F.R.S) in 1920. In 1927 he presided over the Indian Science Congress. Bose had worked all along without the right kind of scientific instruments and laboratory. For a long time he had been thinking of building a laboratory. The result was the 'Bose Research Institute' which is in Calcutta. Even now it is famous as a centre of research. Bose had been collecting funds for this Institute for quite some time. More than sixty-five years ago, he had realised the importance of a research institution in India. While inaugurating the Bose Research Institute he said, "This is not a laboratory but a temple." Such was his devotion to work. He felt everybody must have the same enthusiasm for research in a country. In the Bose Research Institute research is conducted in Botany and Physics - the two branches of science in which Bose had won fame. He worked in this laboratory for 20 years, up to the very end of his life. We should not depend on others to do our work, we ourselves must do our work; but before we can do this we must get over our pride - this was his firm belief. He confessed that he had learnt this lesson from his parents. Nature had always been a source of attraction right from his early age to Bose. There are flowers on plants; flowers give fruits; the leaves fall off; seeds germinate into new plants - we see all these around us. But Bose was interested in these happenings, which to many people seem quite ordinary. He asked others questions; he asked himself, too: 'How do these things happen?' Not always could he satisfy his curiosity. But it was his way to try to find answers to any questions arising in his mind. We may consider here the more important of his discoveries. Plants respond to stimulus from outside. We draw away hand when it touches fire. When it is extremely cold we may even die. Plants also experience heat and cold in this way. This can be measured with a thermometer. At 60 degrees Centigrade a plant will faint because of the extreme heat and at very low temperatures it will react similarly to cold. Plants always react to the rise or fall of temperature in the atmosphere around them. When heat or cold is extreme, plants will faint or may even die. Bose had designed very delicate instruments that could record even this. When a plant is hurt at one point, the shock of this is transmitted to all the other parts and the whole plan gets tired and it bends down. Plants grow every second by 1/50,000th of an inch! How is this to be measured - it is so very, very, very small? Bose himself devised a delicate instrument, which could measure even this length. Plants do not grow in a perfect straight line. There are small twists and turns, Why? The answer Bose found out is very interesting. He said, that plants have positive and negative charges. If one of these pushes a part of the plant forward, the other pushes it backward. The growth of the plant is affected by these pushes and it becomes slightly curved instead of being straight. Plants grow towards light even when kept in a dark place, why? The roots of plants always grow downwards, why? Bose found answers to all these questions. We all know that the lovely flower, the lotus, opens up as the sun rises in the sky. When the sun sets the lotus closes its petals. The popular belief is that this is because the lotus loves the sun. But Bose explained this peculiar behaviour of the lotus. It opens when there is a raise in the temperature and closes as thetemperature drops. The same is true of the sunflower. He called this peculiarity 'the thirst for light'. The other peculiar thing he demonstrated was the way plants behave differently at different times of the day. He established that from 6 in the morning to 3 o'clock in the afternoon the, plants behave in one way; and from 3 in the afternoon to 6 in the morning plants behave differently. As an example he choose a palm tree in Faridpur. This palm in Faridpur would bend down every evening. The people of the place had their own explanation. They believed that the soul of some holy man lived in the tree. Every evening when the temple bells rang, this holy spirit bowed in devotion - this was their belief. But Jagadishchandra Bose discovered the real cause. He gave a scientific explanation. The tree bent down in the evening and raised itself in the morning because of the fall and the rise in the temperature. Water is very essential to plants. The root of the plant absorbs water. But even without roots plants can take in water. This was demonstrated by Bose. He showed that when the root is cut and the plant stem is placed in, water it starts taking in water. Suppose you remove the plant from the soil, and place it upside down (with the branches below and the roots above); what happens? The leaves and the stem absorb water. Bose proved this by means of experiments. The cells of a plant function like a man's heart. The heart contracts and expands to pump blood; in the same way, the cells of a plant expand and contract. This had to be proved by experiments. So, Bose himself devised a new instrument; this could show how the cells worked. Jagadishchandra Bose was famous as a scientist. He brought laurels to his motherland. But his interests were many-sided. He was especially interested in literature and fine arts. The great poet Rabindranath Tagore and Jagadish chandra Bose were very good friends. The first time Tagore visited Bose, he was not at home. Tagore left a bunch of champak flowers. This was the beginning of their friendship. Tagore invited Bose to stay with him for some time. Bose agreed to do so on one condition. The condition was that Tagore should narrate a story to him every day. This is how a number of Tagore's stories came to be written. Have you read the story 'The Cabuliwallah'? It is very fine story; it narrates how a deep and strange friendship grew up between a rough pathan and a tine Bengali girl. This has been translated into several languages and is well known in a number of countries. Tagore wrote this story when Bose was staying with him. And Bose, the great scientist , was also President of the Bengali Sahitya Parishat. We have already seen how Bose honoured the Indian sages of the past. Scientists of other countries praised Bose's important dicoveries; Bose used to say, "The sages of India knew all this long ago". He loved to visit the various shrines of India. Accompained by his wife he would make these trips whenever he could find time. He used to take photographs of the places he visited and had quite acollection of these photographs. He went to places of historical or mythological interest. The famous sculptures and the temple architecture of our land always thrilled him. He visited Sanchi, Chitorgarh, Ajmer and Nainital as well as the cave temples of Orissa and the famous Ajanta and Ellora Caves. He visited the Puri Jagannatha swamy Temple. He also visited well-known places of pilgrimage of South India like Rameshwaram, Madurai and Tanjore. He visited the shrines at the foot of Himalayas; Kedarnath particularly appealed to him. Jagadishchandra Bose was not a proud man. He was simple, affectionate and warm. It is not surprising that many great persons of the day were his friends. Prafulla Chandra Ray, another famous scientist, was one of his close friends. Eminent men like Gopalakrishna Gokhale and Mahatma Gandhi knew and respected him. Sister Nivedita was another good friend. She was an Irish lady; her name was Margaret Nobel. She was the disciple of Swami Vivekananda. She settled down in India and spent her life in the service of the people of this country. She recognized the genius in Bose. Bose toiled hard to educate the people about the importance of science, and Sister Nivedita admired his efforts. So she was keenly looking forward to the birth of the Bose Research Institute. In memory of her, Bose placed in front of the Institute the statue of a woman stepping forward with a light in her hand. He had another good friend, one Mrs.Bull. While touring America he was her guest. She had taken care of him as a mother. When he fell ill in Paris, she traveled to Paris, made arrangements for his treatment and personally looked after him. There were two other friends of his, two giants of the literary world. They were George Bernard Shaw, the English dramatist and Romain Rolland, the French writer. Both of them dedicated one book each to Jagadishchandra Bose. Jagadishchandra Bose was very busy throughout his life. He had no time to think of the problems of the household. His wife Abala Bose looked after their home all by herself; he did not have to think of the management of the house. She was herself a student of medicine when her marriage to Bose was settled.Bose's parents were very kind and generous; they had helped many people with money. So, at the time of Bose's marriage the family was in heavy debts. Jagadishchandra Bose had to repay the debts. So Abala Bose was very, very careful in spending money, and saved as much as possible. Unfortunately the Bose couple had only one child, which did not live long. They looked after the students as their children. Abala Bose started girls' school in Calcutta and took upon herself the responsibility of maintaining it. She went with her husband when he went to foreign countries, and even helped in his scientific work. Jagadishchandra Bose has a permanent place in the world of science, especially in Botany. He began the Age of Modem Science in India and deserves honour for this. He had all the qualities that research requires. He had keen powers of observation and he was patient. He was also a very good lecturer. His students loved his lectures. He did not teach only for the sake of the examination. Students should study books and study what the teacher teaches; but this is not enough; they should use their brains and think for themselves; they should be eager to discover new knowledge - this is what he taught his students. He encouraged them to observe, to experiment and to think, without depending only on books and teachers. Jagadishchandra Bose died in November 1937. To the very end he was busy with research. Wealth and power never attracted Jagadishchandra Bose. He toiled for science like a saint, selflessly. This great scientist is a great example to all. The work of Jagadish Chandra Bose Just one hundred years ago, J.C. Bose described to the Royal Institution in London his research carried out in Calcutta at millimetre wavelengths. He used waveguides, horn antennas, dielectric lenses, various polarisers and even semiconductors at frequencies as high as 60 GHz; much of his original equipment is still in existence, now at the Bose Institute in Calcutta. Some concepts from his original 1897 papers have been incorporated into a new 1.3mm multi-beam receiver now in use on the NRAO 12 Metre Telescope. Introduction James Clerk Maxwell's equations predicting the existence of electromagnetic radiation propagating at the speed of light were made public in 1865; in 1888 Hertz had demonstrated generation of electromagnetic waves, and that their properties were similar to those of light [1]. Before the start of the twentieth century, many of the concepts now familiar in microwaves had been developed [2,3]: the list includes the cylindrical parabolic reflector, dielectric lens, microwave absorbers, the cavity radiator, the radiating iris and the pyramidal electromagnetic horn. Round, square and rectangular waveguides were used, with experimental development anticipating by several years Rayleigh's 1896 theoretical solution [4] for waveguide modes. Many microwave components in use were quasi-optical - a term first introduced by Oliver Lodge [5]. Righi in 1897 published a treatise on microwave optics [6]. Hertz had used a wavelength of 66cm; other post-Hertzian pre-1900 experimenters used wavelengths well into the short cm-wave region, with Bose in Calcutta [7,8] and Lebedew in Moscow [9] independently performing experiments at wavelengths as short as 5 and 6mm. The Researches of JC Bose Jagadish Chandra Bose [10,11,12] was born in India in 1858. He received his education first in India, until in 1880 he went to England to study medicine at the University of London. Within a year he moved to Cambridge to take up a scholarship to study Natural Science at Christ's College Cambridge. One of his lecturers at Cambridge was Professor Rayleigh, who clearly had a profound influence on his later work. In 1884 Bose was awarded a B.A. from Cambridge, but also a B.Sc. from London University. Bose then returned to India, taking up a post initially as officiating professor of physics at the Presidency College in Calcutta. Following the example of Lord Rayleigh, Jagadish Bose made extensive use of scientific demonstrations in class; he is reported as being extraordinarily popular and effective as a teacher. Many of his students at the Presidency College were destined to become famous in their own right - for example S.N. Bose, later to become well known for the Bose-Einstein statistics. A book by Sir Oliver Lodge, "Heinrich Hertz and His Successors," impressed Bose. In 1894, J.C. Bose converted a small enclosure adjoining a bathroom in the Presidency College into a laboratory. He carried out experiments involving refraction, diffraction and polarisation. To receive the radiation, he used a variety of different junctions connected to a highly sensitive galvanometer. He plotted in detail the voltage-current characteristics of his junctions, noting their non-linear characteristics. He developed the use of galena crystals for making receivers, both for short wavelength radio waves and for white and ultraviolet light. Patent rights for their use in detecting electromagnetic radiation were granted to him in 1904. In 1954 Pearson and Brattain [14] gave priority to Bose for the use of a semi-conducting crystal as a detector of radio waves. Sir Neville Mott, Nobel Laureate in 1977 for his own contributions to solid-state electronics, remarked [12] that "J.C. Bose was at least 60 years ahead of his time" and "In fact, he had anticipated the existence of P-type and N-type semiconductors." In 1895 Bose gave his first public demonstration of electromagnetic waves, using them to ring a bell remotely and to explode some gunpowder. In 1896 the Daily Chronicle of England reported: "The inventor (J.C. Bose) has transmitted signals to a distance of nearly a mile and herein lies the first and obvious and exceedingly valuable application of this new theoretical marvel." Popov in Russia was doing similar experiments, but had written in December 1895 that he was still entertaining the hope of remote signalling with radio waves. The first successful wireless signalling experiment by Marconi on Salisbury Plain in England was not until May 1897. The 1895 public demonstration by Bose in Calcutta predates all these experiments. Invited by Lord Rayleigh, in 1897 Bose reported on his microwave (millimetre-wave) experiments to the Royal Institution and other societies in England [8]. The wavelengths he used ranged from 2.5cm to 5mm. In his presentation to the Royal Institution in January 1897 Bose speculated [see p.88 of ref.8] on the existence of electromagnetic radiation from the sun, suggesting that either the solar or the terrestrial atmosphere might be responsible for the lack of success so far in detecting such radiation - solar emission was not detected until 1942, and the 1.2cm atmospheric water vapour absorption line was discovered during experimental radar work in 1944. Figure 1 shows J.C. Bose at the Royal Institution in London in January 1897; Figure 2 shows a matching diagram, with a brief description of the apparatus.
By about the end of the 19th century, the interests of Bose turned away from electromagnetic waves to response phenomena in plants; this included studies of the effects of electromagnetic radiation on plants, a topical field today. He retired from the Presidency College in 1915, but was appointed Professor Emeritus. Two years later the Bose Institute was founded. Bose was elected a Fellow of the Royal Society in 1920. He died in 1937, a week before his 80th birthday; his ashes are in a shrine at the Bose Institute in Calcutta. Figure 2. Bose's apparatus demonstrated to the Royal Institution in London in 1897 [8]. Note the waveguide radiator on the transmitter at left, and that the "collecting funnel" (F) is in fact a pyramidal electromagnetic horn antenna, first used by Bose.
Bose's Apparatus Bose's experiments were carried out at the Presidency College in Calcutta, although for demonstrations he developed a compact portable version of the equipment, including transmitter, receiver and various microwave components. Some of his original equipment still exists, now at the Bose Institute in Calcutta. In 1985 the author was permitted by the Bose Institute to examine and photograph some of this original apparatus.
Figure 3 Bose's diagrams of his radiators. (a) shows the radiator used to generated 5-mm radiation, while (b) shows the arrangement with a lens L at the exit of the waveguide [2]. In some designs the mounting stems for the outer spheres could be inclined to adjust the dimension of the spark gaps. Figure 3 (a) shows Bose's diagram of one of his radiators, used for generating 5mm radiation. Oscillation is produced by sparking between 2 hollow hemispheres and the interposed sphere. There is a bead of platinum on the inside surface of each hemisphere. For some experiments, a lens of glass or of sulphur was used to collimate the radiation - the first waveguide-lens antenna. The lens was designed according to the refractive index measured by Bose at the wavelength in use. Figure 3(b) shows Bose's drawing of such a radiator; the sparks occur between the two outer spheres to the inner sphere, at the focal point of the lens L at the right. Bose was able to measure the wavelength of his radiation with a reflecting diffraction grating made of metal strips [7]. Bose measured the I-V characteristics of his junctions; an example characteristic curve of a "Single Point Iron Receiver" is shown in Figure 6. The junction consisted of a sharp point of iron, pressing against an iron surface, with pressure capable of fine adjustment. The different curves in Figure 6 correspond to different contact pressures. Bose noted that the junction does not obey Ohm's law, and that there is a knee in the curve at approximately 0.45 volts; the junction becomes most effective at detection of short wavelength radiation when the corresponding bias voltage is applied. He made further measurements on a variety of junctions made of different materials, classifying the different materials into positive or negative classes of substance. In one experiment he noted that increasing the applied voltage to the junction actually decreased the resulting current, implying a negative dynamic resistance [15]. Figure 6. The I-V characteristics measured by Bose for a Single Point Iron Receiver. Note the similarity to modern semiconductor junctions, with a knee voltage of about 0.4 volts.
Another of Bose's short-wavelength detectors is the spiral-spring receiver. A sketch of a receiver used for 5-mm radiation is shown in Figure 7; the spring pressure could be adjusted very finely in order to attain optimum sensitivity. The sensitive surface of the 5-mm receiver was 1 by 2 cm. The device has been described recently [3] as a "space-irradiated multi-contact semiconductor (using the natural oxide of the springs)." A surviving, somewhat larger, spiral spring receiver is shown in the photograph Figure 8. The springs are held in place by a sheet of glass, seen to be partly broken in this example.
Figure 9 is Bose's diagram of his polarization apparatus. The transmitter is the box at left, and a spiral spring receiver ('R') is visible on the right. One of the polarisers used by Bose was a cut-off metal plate grating, consisting of a book (Bradshaw's Railway Timetable) with sheets of tinfoil interleaved in the pages. Bose was able to demonstrate that even an ordinary book, without the tinfoil, is able to produce polarisation of the transmitted beam. The pages act as parallel dielectric sheets separated by a small air gap.
Bose experimented with samples of jute in polarising experiments. In one experiment, he made a twisted bundle of jute and showed that it could be used to rotate the plane of polarisation. The modern equivalent component may be a twisted dielectric waveguide. He further used this to construct a macroscopic molecular model as an analogy to the rotation of polarisation produced by liquids like sugar solutions. Figure 11 shows Bose's diagram of the jute twisted-fiber polarisation rotator. Figure 11. Bose's diagram of twisted-Jute polarization elements, used to simulate macroscopically the polarization effect of a certain sugar solutions. The double prism attenuator Bose's investigations included measurement of refractive index of a variety of substances. He made dielectric lenses and prisms; examples are visible in Figures 1 and 2.
One investigation involved measurement of total internal reflection inside a dielectric prism, and the effect of a small air gap between two identical prisms. When the prisms are widely separated, total internal reflection takes place and the incident radiation is reflected inside the dielectric. When the 2 prisms touch, radiation propagates unhindered through both prisms. By introducing a small air gap, the combination becomes a variable attenuator to incident radiation; this is illustrated in Bose's original diagram, shown in Figure 13. Bose investigated this prism attenuator experimentally; his results were published in the Proceedings of the Royal Society in November, 1897 [8]. Schaefer and Gross [16] made a theoretical study of the prism combination in 1910; the device has since been described in standard texts. At the National Radio Astronomy Observatory in Tucson, Arizona a new multiple-feed receiver, operating at a wavelength of 1.3mm, has recently been built and installed on the 12 Metre Telescope at Kitt Peak [17]. The system is an 8-feed receiver, where the local oscillator is injected into the superconducting tunnel junction (SIS) mixers optically. With an SIS mixer receiver the power level of the injected local oscillator is critical; each of the 8 mixers requires independent local oscillator power adjustment. This is achieved by adjustable prism attenuators. Conclusions Research into the generation and detection of millimetre waves, and the properties of substances at these wavelengths, was being undertaken in some detail one hundred years ago, by J.C. Bose in Calcutta. Many of the microwave components familiar today - waveguide, horn antennas, polarisers, dielectric lenses and prisms, and even semiconductor detectors of electromagnetic radiation - were invented and used in the last decade of the nineteenth century. At about the end of the nineteenth century, many of the workers in this area simply became interested in other topics. Attention of the wireless experimenters of the time became focused on much longer wavelengths which eventually, with the help of the then unknown ionosphere, were able to support signalling at very much greater distances. Although it appears that Bose's demonstration of remote wireless signalling has priority over Marconi, he was the first to use a semiconductor junction to detect radio waves, and he invented various now commonplace microwave components, outside of India he is rarely given the deserved recognition. Further work at millimetre wavelengths was almost nonexistent for nearly 50 years. J.C. Bose was at least this much ahead of his time. |
Figure
1. J.C. Bose at the Royal Institution, London, 1897. [13]
Figure
13. Bose's 1897 diagram of the double-prism attenuator.
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