Bharatiya Pragna - Dr. Th Chowdary

150th Birth Year
18
Tribute
used microwaves with time. ...In fact, he had anticipated the existence
wavelengths in the millimeter range, not radio of P-type and N-type semi-conductors.
waves, Considering the very primitive workshop Bose’s first paper published in the Proceed-
facilities available in Calcutta at this time, the comings of the Asiatic Society of Bengalm May 1895,
pact nature of his apparatus excited many and deals with the polarization of electric waves by
drew a great deal of appreciation in England. It double refraction. In October 1895, his first com-
was described in many textbooks of this period by munication to the Royal Society of London was
J. J. Thomson and Poincare. The Daily Chronicle published in its Proceedings. The next year, he was
(England) reported, the inventor has transmit- conferred D. Sc. by London University for his theted
signals to a distance of nearly a mile and sis on Measurements of Electric Rays, Bose went
herein lies the first and obvious and exceedingly to England in 1897, where he not only repeated his
valuable application of this new theoretical demonstrations successfully but also speculated on
marvel.
the existence of electromagnetic radiation from
In recent years, some Indian scientists have the sun. Two years later, Bose unveiled his in-
spearheaded a movement to give Bose his due vention of the mercury coherer with the telephone
recognition as the Father of Wireless Telegra- detector, The same year he unfortunately lost his
phy. For, it was more than a year after the suc- diary containing the account of his invention and a
cessful demonstration of his experiment that prototype of the detector.
Guglielmo Marconi patented this invention. It is Bose devoted a great deal of attention to
believed that it was Bose’s failure to seek a patent the peculiar behaviour of his coherer, which con-
that denied him his due. However, by all accounts, sisted of a number of contacts between metal
Bose was never interested in money. The British filings whose resistance altered under the im-
navy was interested in his coherer (device that pact of electric radiation. Detailed investigation
detects radio waves) to establish radio links be- led him to the view that this coherer effect was
tween ships and torpedo boats. So it is not as if characteristic of a large class of compounds, like
Bose was unaware of the monetary worth of
his findings. He wrote to Rabindranath Tagore in
1901, ....I wish you could see that terrible attachment
for gain in this country.... that lust
for money... Once caught in that trap there
would have been no way out for me.
Later, Bose developed the use of Galena
crystals for making receivers, both for short
wavelength radio waves and for white and ultraviolet
light. His pioneering work in the field was
recognized by his peers. Sir Neville Mott, who won
selenium, iron oxides, etc. In fact, Bose can be
considered a pioneer in the field of investigation
of the properties of photoconductivity and contact
rectification shown by this class of semi-conductors.
His subsequent study of the fatigue phenomena
exhibited by these substances led Bose
to postulate his theory of the similarity of response
in the living and the non-living. He found
that the sensitivity of the coherer decreased when
it was used for a long period -it became tired.
the Nobel Prize in 1977 for his contributions to solid When he gave the device some rest, it regained its
state electronics, went on record stating that, / sensitivity which, in his view, indicated that metals
C. Bose was at least sixty years ahead of his had feelings and memory!
November & December 2008 Bharatiya Pragna