Sisir Kumar Mitra is the doyen of radio science
in India. He is known for his seminal work on ionosphere. The ionosphere,
that extends from about 60 km to several thousand kilometres high
in the atmosphere, plays a major role in long distance radio communications.
The air in the ionosphere is ionized. The name `ionosphere’
was proposed by Robert Alexander Watson Watt, (1892-1973) a British
engineer. The first experimental evidence for the existence of ionosphere
was provided by Edward Victor Appleton (1832-1965) and Samuel Jackson
Barnett (1873-1956) in 1925. The ionosphere has been characterized
by different layers like F, E, D, and C in order of decreasing attitude.
The existence of E-layer was first predicted by Oliver Heaviside
(1850-1925) and Arthur Edwin Kennely (1861-1989) and the F-layer
was discovered by Appleton. The first experimental evidence of E-region
of the ionosphere was obtained by Mitra and his coworkers in 1930.
Mitra and his co-worker P Syam announced the reception of regular
echoes from heights around 55 km and they called it D-layer, the
existence of which was originally reported by Appleton in 1928.
Mitra’s group detected echoes from as low as 20 km. The very
low level reflections were believed to come from a hitherto unsuspected
layer. Mitra called this layer C-layer. One of the most important
works of Mitra was his explanation for the Appleton ionization anomaly.
Mitra introduced `wireless’ to the post-graduate
course in physics at the Calcutta University. This marked the beginning
of radio science teaching in India. He established a strong ionospheric
research school at Calcutta. It was under Mitra’s leadership
a full-fledged Department of Radio Physics and Electronics was created
in the Calcutta University. This was the first teaching and research
department in India in Radio Physics, which later became the Institute
of Radio Physics and Electronics. India’s first entry into
organized international scientific research was made possible by
Mitra, when his laboratory participated in the second international
polar year (IPY2-1932), for specific investigations on different
aspects of the ionosphere. He established the first ionospheric
field station at Haringhata, about 45 km north of Kolkata (then
Calcutta) for ionospheric investigations in 1950. Mitra played a
pioneering role in radio broadcasting in India.
To his students, Mira was a great source of inspiration.
He used to emphasise that only with sustained efforts one can be
successful as a researcher. He was against the concept of rigidly
specified task and he never exercised rigid control over his research
students. He believed that one could be a successful teacher in
higher education only if one had oneself made some contribution
to the subject.
Sisir Kumar Mitra was born in Kolkata on 24 October
1890. His parental home was at Konnagar in Hoogly district. His
father Joykrishna Mitra was a school teacher. Joykrishna married
Saratkumari, who came from a Brahmo family, in 1878 against the
wishes of his parents. As a result he was disinherited from his
parental property and he had to leave his parental house. The newly
married couple moved to Midnapur, the hometown of Saratkumari, where
they lived about a decade. In 1889, they moved to Kolkata, where
Joykrishna started teaching in a school. At the time of Sisir Kumar’s
birth, his mother was a student in the Campbell Medical School.
After passing the final examination in 1892, Saratkumari got an
appointment in Lady Dufferin Medical Hospital in Bhagalpore in Bihar
and the whole family moved there. Joykrishna also managed to get
an appointment as clerk in the local municipal office.
Mitra started his school education in the Bhagalpore
Zilla (District) School. After passing the entrance examination
from the Zilla School Mitra joined the T.N.J. College, Bhagalpore,
from where he passed his FA Examination. He returned to Kolkata
in 1908 to join the Presidency College as a B.Sc. student where
he came into contact with J.C. Bose and P.C. Ray, the two pioneers
of modern scientific research in India. He used to be fascinated
by instruments designed and constructed by J.C. Bose for studying
the properties of microwave and to detect various responses of plants.
In 1912, he passed out of Presidency College taking his M.Sc. degree
in physics and topping the list of successful candidates.
The environment of the Presidency College had a
strong influence on Mitra. He had made up his mind to dedicate himself
to scientific research. And he also got an opportunity to work under
Jagadis Chandra Bose in the Presidency College immediately after
his MSc results were out. In those days it was not easy to get a
research fellowship. His widowed mother, who was supporting his
education at Kolkata, badly needed some financial help to run the
family. Her own income was not sufficient. So when Mitra got an
appointment as Lecturer in the T. N. J. College at Bhagalpore, from
where he passed his FA Examination, he left Kolkata to join the
same. From Bhagalpore he shifted to Bankura in West Bengal on being
appointed a lecturer in the Christian College. He spent four years
teaching in colleges but at the same time harbored a burning desire
in his mind to pursue a research career. Of course, there was no
scope for carrying out researches in these mufassil colleges. But
then a person like Mitra could not sit idle. So he started devising
ingenuous demonstration experiments with whatever he could collect
from the impoverished college laboratory, for illustrating his class
lectures. He also started writing popular science articles in Bengali.
Mitra finally got an opportunity to realize his
dream of carrying out research. While Mitra was teaching in College,
Sir Asutosh Mookerjee, the then Vice-Chancellor of the Calcutta
University was trying to initiate postgraduate teaching and research
in science. With the untiring efforts of Sir Asutosh, the University
College of Science was established in 1916. Mitra was one among
those who were invited by Mookerjee to join the newly created Department
of Physics in the newly created University college of Science. Mitra,
who was then twent-six years old, joined the Department as Lecturer.
This marked the beginning of Mitra’s outstanding scientific
career. C. V. Raman joined the Department as Palit Professor. Mitra
started working under Raman’s guidance on interference and
diffraction of light. Mitra worked in the laboratory of C.V. Raman
in the Indian Association for the Cultivation of Science. It took
him only three years to complete his doctorate thesis which enabled
him to get a D.Sc. from Calcutta University in 1919.
In 1920 Mitra went to the University of Sorbonne
in Paris where he joined the research group of Charles Fabry (1867-1945),
who had discovered ozone in the upper atmosphere in 1913. At Fabry’s
Laboratory Mitra worked on the determination of wavelength standards
in the region 2000-2300 angstrom of the copper spectrum. Based on
this work he got his second doctorate in 1923. From Sorbonne he
went to work under Marie Curie at the Institute of Radium. However,
he did not stay there long. He went to work with Prof. Gutton, who
was working on radio valve circuits in the Institute of Physics
at the Universtiy of Nancy, Paris. Though he spent only a few months
at Gutton’s Laboratory but it was here that he finally made
up his mind to make his career in radio research.
Why did he choose to shift to radio research though
he was successful in spectroscopic research? “May be”,
as J. N. Bhar wrote, “he had been so deeply influenced by
Bose’s experiment on wireless waves that a desire for doing
research in this line lay hidden in his subconscious mind”.
It may be noted that Mitra witnessed Bose’s experiments when
he was a student in Presidency College. Whatever might be the reason
it was certainly a bold decision. When Mitra took his decision to
pursue a career in radio science, it was still in its infancy. Radio
science was not a part of the curriculum of any university in India
and so there was no question of availability of any research facility
in the subject. Without being deterred by these obstacles he wrote
to Sir Asutosh Mookerjee about his decision. Sir Asutosh in his
reply dated 10th May 1923 wrote: “I am glad to receive your
letter dated 18th April and to hear that you have been so successful
in your work. The course of investigation you suggest as to signals
by wireless telegraphy is very attractive. Do please draw up a scheme
and make it as inexpensive as possible. I shall see what we can
do. But you must rest assured that there will be plenty of opposition.
That need not frighten us; we shall have to fight our way through.”
Mitra returned from France at the end of 1923 and
he was appointed Khaira Professor of Physics. He became a part of
the team consisting of C. V. Raman, D. M. Bose and others who organised
the post-graduate teaching in physics in the Calcutta University.
Mitra’s task was to establish the `wireless section’
for teaching and carrying out research in the new subject. With
the active support of Sir Asutosh Mookerjee, Mitra was able to start
for the first time postgraduate teaching and research on wireless
To have an understanding of the significance of
Mitra’s work one should have an idea of ionosphere and what
was the status of its understanding when Mitra started his work.
The presence of ionosphere is vital for long distance radio communication.
Ionosphere is a region of the upper atmosphere that reflects short
radio waves enabling transmission to be made round the curved surface
of the earth by sky waves. All regions of our atmosphere are defined
in terms of ionization, temperature and composition. The region
which extends form 60 km to several thousand kilometers above the
earth is called ionosphere. The existence of an ionized layer in
the atmosphere or the ionosphere was first suspected in 1882 by
the Scottish physicist Balfour Stewart. He proposed the existence
of a layer of air capable of conducting electricity in the upper
atmosphere, and whose presence, Stewart thought, was the reason
for the continuous minor variation in Earth’s magnetic field.
However, Stewart’s prediction remained mostly unnoticed till
1901 when Guglielmo Marconi (1874-1937) succeeded transmitting wireless
signals across the Atlantic Ocean, a distance of about 2800 kilometres.
For physicists this was an unexpected achievement. Because like
light, radio waves also travel in straight lines and so their detection
on the earth’s surface should not be possible beyond the line
of sight. To explain the propagation of radio waves the existence
of an electrically conducting air layer, as proposed by Stewart,
was again invoked. This was in 1902. And this time this was proposed
independently by Oliver Heavside and Arthur Kennelly. They proposed
that such a layer situating about at a height of 80 km in the atmosphere
would act as a repeater station by reflecting radio waves at a considerable
distance beyond the horizon. The proposed layer came to be known
as Kennelly-Heaveside layer, the existence of which was experimentally
proved in 1924 by Edward V. Appleton and Samuel Jackson Barnett.
They devised two alternative methods –the angle of incidence
method and the frequency change method -- to determine experimentally
the location of the ionized layer which vary in behavior with the
position of the sun and with sunspot cycle.
G. Breit and M. A. Tuve in the United States devised
a technique for determining the height of the reflecting region.
Radio waves travel with the speed of light. Thus the height of the
reflecting region can be caculated if one can measure the time taken
by the transmitted radio waves back to the earth. Breit and Tuve
transmitted a short pulse of radio waves upward and then they determined
the time taken for the pulse to be reflected back to the receiver,
a few kilometers away, by means of an oscilloscope. In this way
they found the altitude of the Kennely-Heaviside layer in the range
Appleton, in the course of his investigation with
radio waves of shorter wavelengths, another reflecting layer at
the height of roughly 200 to 400 km. This layer was called Appleton
layer. The names of these two layer were changed by Appleton as
E (Kennelly-Heaveside layer) and F (Appleton layer) layers. This
is the nomenclature now universally followed. Subsequently another
layer, a layer below the E layer, was discovered. This layer was
called D-layer. The D-layer which is located between 50 and 90 km
altitude disappears during the day. The F-layer splits into two
different regions, namely F1 and F2. The F1 region which exists
only in daytime, has a peak density around 200km. In the F2 region,
the altitude of the peak density occurs at about 300km in daytime
and it shifts to higher altitude in the night. The E-region is between
90 and 160 km and the F-region (sometimes called the Appleton layer)
is from 160 km up to about 400 km. These early experiments carried
out by Appleton and his co-workers attracted the attention of Mitra
and he decided to conduct similar investigations in his newly established
laboratory. He could motivate a small team of young and enthusiastic
scientists to take up this challenging work.
Mitra’s group could measure the heights of
the different layers of the ionosphere by an instrument designed
and built indigenously. The investigations carried out by Mitra’s
laboratory not only provided the first general picture of the ionospheric
condition in a sub-tropical region of low altitude like Calcutta
but experimental results obtained by Mitra and his coworkers also
threw considerable light on the effect of thunderstorm, magnetic
storm and meteoric shower on upper atmospheric ionization. Mitra
also gave a theory of the D-layer which was first reported by Appleton
in 1928. D-layer is an absorbing layer formed during the daytime
just below the E-layer, the echo from this layer is only occasionally
observed. Mitra and his co-workers conclusively established the
existence of this layer. The experimental evidence for the E-layer
of the ionosphere was obtained for the first time by Mitra’s
group. H. Rakshit working under Mitra developed the first indigenous
equipment for ionospheric studies by the angle of incidence method.
The Calcutta Station of the Indian State Brodcasting Service made
available its medium wave transmitter to Mitra’s group. They
often broadcast transmissions outside regular programme period.
Utilising these facilities Mitra’s group experimentally proved
the existence of the E-layer.
Mitra’s group detected reflections from as
low as as 20 km. Mitra proposed that such low-level reflections
were coming from a hitherto unsuspected layer. Mitra called this
layer C-layer. At the beginning the discovery was received with
certain amount of skepticism by the western scientists, but later
it was corroborated by many observers in England and America. The
echoes originating from such a low layer may be due to reflection
from the temperature discontinuities and from moisture layer in
the lower atmosphere.
While developing teaching and research facilities
at the Calcutta University Mitra got involved in the development
of broadcasting in India. A private company called the Indian States
and Eastern Agency had installed the country’s first broadcast
transmitter in Kolkata in 1923. The Radio Club of Bengal, a registered
society, under the Chairmanship of J.R. Stapleton, published a journal
called “Radio“ for creating interest in this newly found
subject by providing relevant information. In 1926, before the establishment
of the Indian Broadcasting Company in 1927, Radio Club’s transmitters
at Dalhousie Square broadcast regular programme every evening. Mitra
and his coworkers constructed another transmitter and installed
in the newly established Wireless Laboratory in the University College
of Science in Calcutta. Its call sign was 2 CZ. It is worthwhile
to note that there was a time when Mitra’s transmitter in
his Wireless Laboratory and the Radio club’s transmitter at
Dalhousie Square were the only ones broadcasting regular programme
in the Eastern region of India.
The wireless laboratory established by Mitra started
working on the measurement of the atmospherics and for this purpose
a huge aerial connected to a valve amplifier and an automatic recording
devise was set up.
With the financial assistance from the Council
of Scientific and Industrial Research, Mitra established a field
station for ionospheric work at Haringhata- a village about 50 km
from Calcutta following a suitable capital and recurring grant sanctioned
by the council of Scientific and Industrial Research in 1949. An
ionosounde, donated by the Commonwealth Scientific and Industrial
Research Organization of Australia was installed in the station.
This was the first ionosphere field station of its kind in India.
In 1955, the station started round the clock observations of the
Mitra’s well-know treatise, The Upper Atmosphere, was his
major scientific contribution. The idea of writing such a book arose
in Mitra’s mind in 1935. In that year the National Institute
of Sciences of India (later renamed as Indian National Science Academy)
organised a symposium on ionosphere. Mitra was invited to open the
symposium, which was held in August 1935. His opening address was
titled `Report on the Present State of our Knowledge of the Ionosphere’.
The Report, which was a comprehensive account of the existing information
on the ionosphere, was welcomed by scientists working on ionosphere
all over the world. This prompted Mitra to think of writing a treatise
on the upper atmosphere, of which the ionosphere was only a part.
It took ten years to finalise the manuscript. This was the `First
heroic attempt’, as Sir Edward Appleton remarked, to put together
in one volume the results of investigations in many different fields
all concerned directly or indirectly with the upper atmosphere.
It is worthwhile to quote here A. P. Mitra, one of Sisir Kumar Mitra’s
illustrious students on the significance of The Upper Atmosphere.
A. P. Mitra wrote: “The Upper Atmosphere was a milestone in
atmospheric science. It considered for the first time the atmospheric
environment as a whole, neutral and ionized, its thermal structure
and distribution of constituents, its motions, the interaction of
solar radiation and particle stream with these gaseous constituents,
and the mechanism of airglow. The ionosphere was treated as only
a part of this vast panorama and interlinked the Sun, the Earth
and the atmosphere. This was then an entirely new concept. Secondly,
deviating from the then existing practice of studying the ionosphere
from the point of view of propagation of radio waves, Mitra viewed
the exploring radio waves as a remote sensing tool, sensing levels
which could not be reached were balloons and with only beginning
to be explored by rockets…Even in this vastly changed (and
greatly expanded) canvas, much of the information given in The Upper
Atmosphere and the results of his scientific investigation stand
as benchmark.” There were other books of high repute on ionosphere
like S. Champan and D J Bartel’s Geomagnetism and J.A. Fleming’s
Terrestrial Magnetism and Electricity, but they dealt with specialized
topics. So Mitra’s book became indispensable as a reference
book for all those who were interested in upper atmospheric research.
However, the publication of the treatise was not a smooth affair.
Mitra and his colleagues who worked very hard to finalise the manuscript
wanted to get it published by a reputed foreign publisher. Accordingly
Mitra wrote to a few reputed publishers giving the list of contents.
But none came forward to undertake its publication. It is interesting
to quote the letter that he got from one of the publishers rejecting
his manuscript. The publishers wrote: “We have given very
careful consideration to your letter of May 16th. Your name, of
course, is well-known to us, and we naturally are assured that your
treatise on the Upper atmosphere is an admirable work. We are sorry
to say, however, that for various reasons we do not think it would
be a practicable proposition for us to undertake its publication.
In the first place, from what you say, it is a
very large book and would be extremely expensive to produce even
in India. Of course, it would be better to have it printed in this
country, but that would be even more expensive. From previous experience
of books of this nature we feel very doubtful whether it would have
a large enough sale to cover the expense of publication; in fact
we anticipate that it would involve us in a considerable financial
Books of this kind really ought to be published
by the University Presses who exist largely in order to publish
learned works whose appeal is very limited. A further consideration
is that even in the small field covered by your book it would have
to compete with Chapman & Bartel’s Geomagnetism and works
by Sir Napier Shaw.
On the whole, therefore, we are very sorry to say
that we can only thank you and regret that we feel unable to publish
the work. We are returning the list of contents which you kindly
There is no wonder that such a reception from the
publishers disappointed Mitra and his groups. At this juncture Meghnad
Saha came in their rescue. At that time Saha was the President of
the Asiatic Society of Bengal. Saha decided that the Asiatic Society
would undertake the publication of the Mitra’s manuscript,
however costly the publication might be. Thus the Asiatic Society
undertook its publication as one of its Memoirs and the first edition
of The Upper Atmosphere came out in 1947. The book was widely appreciated
and the first edition of 2000 copies was sold within three years.
This was certainly a great achievement. In 1952 the Asiatic Society
brought out a revised edition of the book The entire book was translated
in Russian and was published by the foreign Language Publishing
House, Moscow in 1955.
Another scientific problem in which Mitra got involved
was that of active nitrogen which he thought would solve the problem
of the night sky luminescence. He believed that the faint glow in
the night sky was due to mutual neutralisaiton of ions and electrons
in the upper atmosphere. According to the theory propounded by Mitra
in 1943, the after glow is emitted in the act of neutralisaton of
N2+ ions by recombination with electrons which is a three-body collision
process. The persistence of the glow was due to the fact that the
third body is rarely found in the upper atmosphere and so the recombination
process was delayed. In 1945 Mitra published a book titled “Active
Nitrogen: A New Theory”. Mitra’s theory was criticized
by pointing out that the presence of N2+ ions in the glowing gas
could not be experimentally detected. He modified his theory by
proposing that active nitrogen is a mixture of nitrogen atoms in
the ground state and metastable state, a product of dissociative
recombination of N2+ and electrons. So N2+ ions are not the active
substance but they together with electrons are the parent bodies
of the active substances.
In the late 30s Mitra felt the necessity of having
an independent postgraduate department of electronics and radiophysics
and in 1945, he submitted a proposal to the Calcutta University
for creating such a department. Though the University accepted the
proposal, it could not be implemented due to financial constraints.
The Department came into being in 1947 with the availability of
funds from Ministry of Education, Government of India. The Department
was transformed into the Institute of Radio Physics and Electronics,
which was later selected by the University Grants Commission, as
one of the first five centers of advanced study under a scheme sponsored
jointly with UNESCO.
It was Mitra who felt the need of an all India
Radio Research Organisation. As a first step towards realization
of this goal Mitra decided to win the support of the prominent British
scientists for his proposal. In his lecture before the Maxwell Society
in 1936 Mitra not only highlighted the need of greater cooperation
between the ionospheric scientists working in different countries
but he also raised the question of establishing a co-ordinating
body in India on the lines of Radio Research Board of England. For
discussing the desirability of creating such a Board in India he
invited leading British scientists to a dinner on May 05, 1936.
The guests included Sir E. V. Appleton, Sydney Chapman (1888-1970),
Sir Robert Alexander Watson-Watt (1892-1973), Edward Neville da
Costa Andrade (1887-1971), R. A. Gregory, the distinguished editor
of Nature and many others. All the assembled guests strongly favoured
the idea mooted by Mitra. Gregory thought it fit to write an editorial
on it in Nature. He wrote: “The time would now appear to be
very opportune for considering the establishment of a similar Radio
Research Board in India, where fundamental research in radio communication
has so far been limited to the activities of quite small bands of
workers in different universities, notably those under Prof. S.
K. Mitra at Calcutta and under Prof. M. N. Saha at Allahabad…It
is surely time that India was able to take its place in a such a
world-wide scheme (of radio research), and it is to be hoped that
those in a position to do so will foster the inauguration of a suitable
Radio Research Board and provide the necessary funds to initiate
its work. The research already carried out in India indicates that
the Universities are ready to provide a programme of problems of
a fundamental nature, and even the nucleus of a staff of trained
personnel, keen and enthusiastic to continue their investigations
which are at present being limited through lack of resources.”
After coming back to India Mitra launched a strong campaign for
establishing a Radio Research Board. But while his proposal was
strongly supported by the British scientists but that did not have
much impact on the authorities in India. Meghnad Saha, who was then
at Allahabad, lent strong support to Mitra’s cause. And when
Saha came back to Kolkata in 1938 they together renewed their campaign
with greater vigour. Finally the Radio Research Committee was formed
in 1942 under the Department of Scientific and Industrial Research,
then functioning under the Department of Commerce, Government of
India. Mitra was appointed as the Chairman of the Committee. This
was undoubtedly a major step in promoting radio research in the
country. After the appointment of the Radio Research Committee a
number of radio research centers grew up in the country.
Mitra’s concern for industrial development
in the country is well known. While referring to the creation of
the Council of Scientific and Industrial Research, in his Presidential
Address at the Silver Jubilee of the National Institute of Science
Mitra said: “Much of this increased scientific activity has
been due to the support which scientific research began to receive
from the Government with the establishment in 1940, of the Board
of Scientific and Industrial Research, which later became one of
the component units of the wider organization, the Council of Scientific
and Industrial Research (CSIR). Indeed, the adoption of the policy
of sponsoring and encouraging scientific research at the government
level—was the greatest single event in the history of the
progress of science in the country in the last quarter of a century.”
He initiated two industrial schemes in his laboratory. The first
was the production of microphones and loudspeakers which resulted
in the development of a carbon microphone and loudspeaker with raw
materials available indigenously. The second scheme was on the production
of electron tubes, which led to the fabrication of radio valves
for the first time India. The technical knowledge involved were
developed in his laboratory. Though this scheme was abandoned in
1954, the experience gained and the equipment assembled led to the
establishment of Electron Tube Laboratory of the Institute of Radio
Physics and Electronics.
Mitra retired from the Calcutta University in 1955.
He was appointed as Emeritus Professor by the University. Mitra
was persuaded by the then Chief Minister of West Bengal to head
the West Bengal Board of Secondary Education. At the time Mitra’s
taking over its Administratorship , the Board was in a very bad
shape. Within a short span of time Mitra made the Board an efficient
organization. It was under his Adminstratorship that the Board introduced
the Higher Secondary Syllabus in the Schools in 1957. It may be
noted here that the transition from the School Final to the Higher
Secondary curriculum was not only beset with difficulties but the
time given to Mitra to effect the change over was extremely short.
But Mitra succeeded in holding the examination in time.
Mitra was intimately associated with the Indian
Science Congress Association since 1935 when he became the local
secretary. The success of the Silver Jubilee session of the Science
Congress held at Calcutta in 1938 under the Presidentship of Sir
James Jeans was to a large extent was due to the hard work and organizational
ability of Mitra. He served as General Secretary of the ISCA from
1939 to 1944. He was elected sectional president in 1934 when physics
and mathematics was combined into one section. In 1955, he become
the General President. Mitra was closely connected with Indian Association
for the Cultivation of Science since the early twenties when he
worked under C.V. Raman. He served the Association in several capacities,
as its Secretary, as a member of the council, as Vice President,
and as one of its trustees. He played an important role alongwith
M.N. Saha in expansion of the activities of the Indian Science News.
Association since its inception and acted as its Secretary, Editor
Vice President, and as one of its trustees. He helped to improve
the standard and circulation of the Association’s journal
Science and Culture. He was a founder member of National Institute
of Science (later renamed as Indian National Science Academy) and
became its President in 1956. He served as President of Asiatic
Society of Bengal during 1951-52.
Mitra was a strict disciplinarian. After the untimely
death of his wife, Mitra had to look after his children. This he
did without allowing his scientific activities by this additional
responsibility. Besides his interest in scientific activities Mitra’s
only pastime was chess, which he used to play on Sundays with his
friends for hours together. Commenting on Mitra’s personal
traits J.N. Bhar wrote : “Reserved in appearance, Prof. Mitra
exercised unusual restraint on his speeches and movements. He impressed
those around him with his high regard for discipline, exemplary
devotion to duty, keen sense of responsibility and his concern for
precision and perfection in any work done by himself and under his
supervision. Punctuality was inherent in his nature so much so that
his associates often wittingly remarked that one could check time
by noting his movement. Either at home or in office, his scrupulous
observance of rules and discipline surprised even his subordinates.
In all spheres, his love of order, cleanliness and beauty was easily
noticeable. In short, his attention to neatness in deeds and words,
in manners and appearances and in his dealing with others was remarkable.
Neatness was indeed his way of life.”
Honours had come thick on Mitra. He was the recipient
of King Geoge V. Silver Jubilee Medal in 1935. Joy Kissen Mukherjee
Gold Medal of the Indian Association for the Cultivation of Science
in 1943, and the Science Congress (Calcutta) Medal of the Asiatic
Society in 1956. In 1958 he was elected Fellow of the Royal Society,
London for his contribution to the study of upper atmospheric phenomena.
He received the Presidential Award Padmabhushan in 1962.
In April 1963 Mitra was appointed as National Research
Professor and Mitra thought to utilize this opportunity for preparing
a revised third edition of The Upper Atmosphere. But this did not
happen. This pioneer of radio research died on 13 August 1963 leaving
unfinished two tasks he had set for himself – a third revised
edition of The Upper Atmosphere and a textbook of quantum mechanics
based on lectures he delivered in the post graduate classes.
For Further Reading
1. Sisir Kumar Mitra by J. N. Bhar in Biographical
Memoirs of Fellows of the National Insitute of Sciences of India,
Vol.1, New Delhi, 1966.
2. Sisir Kumar Mitra by A. P. Mitra, Resonance,
3. Professor Sisir Kumar Mitra—As I Remember
Him, Mrinal Kumar Das Gupta, Resonance, July 200.
4. Ionosphere and its Influence on Radio Communication
by R. S. Dabas, Resonance, July 200.