Sir Jagadis Chunder Bose, His Life and Speeches

Appointed as a Professor

After having completed his education abroad. Jagadis chose the teaching of Science as his vocation. He was appointed as Professor of Physical Science at the Presidency College, Calcutta. He joined the service on the 7th January, 1885. Although he was appointed in Class IV of the then Bengal Educational Service, (which afterwards merged in the present Indian Educational Service), he was not admitted to the full scale of pay of the Service. He, being an Indian, was allowed to draw only two-thirds the pay of his grade. This humiliating distinction was, however, removed in his case, on the 21st September 1903, when the bureaucracy could not any longer ignore the pressure of enlightened opinion that was brought to bear on it.

His Researches on Electric Waves

It was in 1887, some times after Professor J. C. Bose had joined the Presidency College, Hertz demonstrated, by direct experiment, the existence of Electric Waves--the properties of which had been predicted by Clerk Maxwell long before. This great discovery sent a reverberation through the gallery of the scientific world. And, at once, the scientists in all countries began to devote their best energies to explorations in this new Realm of Nature. Young J. C. Bose--who had drunk deep at the springs of Scientific Knowledge and whose imagination had been very deeply touched by the scientific activities of the West and who had in him the burning desire that India should 'enter the world movement for that advancement of knowledge'--also followed suit.

Difficulties of Researches

When, however, Prof. J. C. Bose joined the Presidency College, there was no laboratory worth the name there, nor had he any of 'those mechanical facilities at his disposal which every prominent European and American experimental scientist commands'. He had to work under discouraging difficulties before he could begin his investigations. He was, however, not a man to quarrel with circumstances. He bravely accepted them and began to work in his own private laboratory and with appliances which, in any other country, would be deemed inadequate. He applied himself closely to the investigation of the invisible etheric waves and, with the simple means at his command, accomplished things, which few were able to perform in spite of their great wealth of external appliances.

As the wave-length of a Hertzian (electric) ray was very large--about 3 metres[8] long--compared with that of visible light, considerable difficulties were experienced in carrying on experiments with the same. It was thought, for instance, that very large crystals, much larger than what occur in nature, would be required to show the polarisation of electric ray. Prof. Bose who 'combined in him the inventiveness of a resourceful engineer, with the penetration and imagination of a great scientist'--designed an instrument which generated very short electric waves with a length of about 6 millimetres or so. And, by working with Electric radiations having very short wave-lengths, he succeeded in demonstrating that the electric waves are polarised by the crystal Nemalite (which he himself discovered) in the very same way as a beam of light is polarised by the crystal Tourmaline. He then showed that a large number of substances, which are opaque to Light (e.g. pitch, coal-tar etc.) are transparent to Electric Waves. He next determined the Index of Refraction of various substances for invisible Electric Radiation and thereby eliminated a great difficulty which had presented itself in Maxwell's theory as to the relation between the index of refraction of light and the di-electric constant of insulators. He then determined the wave length of Electric Radiation as produced by various oscillators.

HIS EARLY CONTRIBUTIONS AND THEIR APPRECIATIONS

His first contribution was 'On Polarisation of Electric Rays by Double Refracting Crystals.' It was read at a meeting of the Asiatic Society of Bengal, held on the 1st May 1895, and was published in the Journal of the Society in Vol. LXIV, Part II, page 291. His next contributions were 'On a new Electro polariscope' and 'On the Double Refraction of the Electric Ray by a Strained Di-electric.' They appeared, in the Electrician, the leading journal on Electricity, published in London. These 'strikingly original researches' won the attention of the scientific world. Lord Kelvin, the greatest physicist of the age, declared himself 'literally filled with wonder and admiration for so much success in the novel and difficult problem which he had attacked.' Lord Rayleigh communicated the results of his remarkable researches to the Royal Society. And the Royal Society showed its appreciation of the high scientific value of his investigation, not only, by the publication, with high tributes, of a paper of his 'On the Determination of the Indices of Electric Refraction,' in December 1896, and another paper on the 'Determination of the Wave-length of Electric Radiation,' in June 1896, but also, by the offer, of their own accord, of an appropriation from the Special Parliamentary Grant made to the Society for the Advancement of Knowledge, for continuation of his work.

In recognition of the importance of the contribution made by Prof. Bose, the University of London conferred on him the Degree of Doctor of Science and the Cambridge University, the degree of M.A., in 1896. And, to crown all, the Royal Institution of Great Britain--rendered famous by the labour of Davy and Faraday, of Rayleigh and Dewar--honoured him by inviting to deliver a 'Friday Evening Discourse' on his original work. It would not be out of place to observe that the rare privilege of being invited to deliver a 'Friday Evening Discourse' is regarded as one of the highest distinction that can be conferred on a scientific man.

HIS FIRST SCIENTIFIC DEPUTATION. (1896-97)

The Government of India showed its appreciation of his work by deputing him to Europe to place the results of his investigations before the learned Scientific Bodies. He remained on his Deputation from the 22nd July 1896 to the 19th April 1897. He read a paper 'On a complete Apparatus for studying the Properties of Electric Waves' at the meeting of British Association, held at Liverpool, in 1896. He then communicated a paper 'On the Selective Conductivity exhibited by Polarising Substances,' which was published by the Royal Society, in January 1897. He next delivered his 'Friday Evening Discourse,' at the Royal Institution, 'On Electric Waves,' on the 29th January 1897. "There is, however, to our thinking" wrote the Spectator at the time "something of rare interest in the spectacle presented of a Bengalee of the purest descent possible, lecturing in London to an audience of appreciative European savants upon one of the most recondite branches of the modern physical science." He was then invited to address the Scientific Societies in Paris. "Prof. J. C. Bose" wrote the Review Encyclopedique, Paris "exhibited on the 9th of March before the Sorbonne, an apparatus of his invention for demonstrating the laws of reflection, refraction, and polarisation of electric waves. He repeated his experiments on the 22nd, before a large number of members of the Academie des Sciences, among whom were Poincare, Cornu, Mascart, Lipmann, Cailletet, Becquerel and others. These savants highly applauded the investigations of the Indian Professor." M. Cornu, President of the Academy of Science, was pleased to address Professor Bose as follows:--

"By your discoveries you have greatly furthered the cause of Science. You must try to revive the grand traditions of your race which bore aloft the torch light of art and science and was the leader of civilization two thousand years ago. We, in France applaud you." This fervent appeal, we shall see, as we proceed, did not go in vain.

He was next invited to lecture before the Universities in Germany. At Berlin, before the leading physicists of Germany, he gave an address on Electric Radiation, which was subsequently published in the Physikaliscen Gesellschaft Berlin, in April 1897.

Further Researches on Electric Waves

Having received the most generous and wide appreciation of his work, Dr. J. C. Bose continued, with redoubled vigour, his valuable researches on Electric Waves. He studied the influence of thickness of air-space on total reflection of Electric Radiation and showed that the critical thickness of air-space is determined by the refracting power of the prism and by the wave-length of the electric oscillations. He next demonstrated the rotation of the plane of polarisation of Electric Waves by means of pieces of twisted jute rope. He showed that, if the pieces are arranged so that their twists are all in one direction and placed in the path of radiation, they rotate the plane of polarisation in a direction depending upon the direction of twists; but, if they are mixed so that there are as many twisted in one direction as the other, there is no rotation.[9] He communicated to the Royal Society the results of his new researches. And the Royal Society published, in November 1897, his papers 'On the Determination of the Index of Refraction of glass for the Electric Ray' and 'On the influence of Thickness of Air-space on Total Reflection of Electric Radiation' and, in March 1898, his further contributions 'On the Rotation of Plane of Polarisation of Electric Waves by a twisted structure' and 'On the Production of a "Dark cross" in the Field of Electro-magnetic Radiation.'

Self-recovering "coherer"

The study of Electric Waves by Dr. J. C. Bose led not only to the devising of methods for the production of the shortest Electric Waves known but also to the construction of a very delicate 'Receiver' for the detection of invisible other disturbances. The most sensitive form of detector hitherto known was the "Coherer." One of the forms made by Sir Oliver Lodge consisted simply of a glass tube containing iron turnings, in contact with which were wire led into opposite ends of the tube. The arrangement was placed in series with a galvanometer and a battery; when the turnings were struck by electric waves, the resistance between loose metallic contacts was diminished and the deflection of the galvanometer was increased. Thus the deflection of the galvanometer was made to indicate the arrival of electric waves. The arrangement was, no doubt, a sensitive one, but, to get a greater delicacy, Dr. Bose used, instead of iron turnings, spiral springs which were pushed against each other by means of a screw.[10] Still the arrangement laboured under one great disadvantage. The 'receiver' had to be tapped between each experiment. So something better than a 'cohering' receiving was needed--something that was self-recovering, like a human eye. To discover that something, Dr. Bose began a study of the whole theory of 'coherer action.' It was hitherto believed that the electric waves, by impinging on iron and other metallic particles in contact, brought about a sort of fusion--a sort of 'coherence'--and that the diminution of resistance was the result of that 'coherence.' To satisfy himself as to the correctness of this theory, Dr. Bose engaged himself in a most laborious investigation to find out the action of electric radiation not only on iron particles but on all kinds of matter and ultimately discovered the surprising fact that, though the impact of electric waves generally produced a diminution of resistance, with potassium there was an increase of resistance after the waves had ceased.[11] This discovery at once showed the untenability of the old theory and pointed to the conclusion that the effect of electric radiation on matter is one of discriminative molecular action--that the Electric Waves produced a re-arrangement of the molecules which may either increase or decrease the contact resistance. It may be incidentally mentioned here that this detection of molecular change in matter under electric stimulation has given rise to a new theory of photographic action.