Jagdish Chandra Bose

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Jagdish Chandra Bose

Introduction

Jagdish Chandra Bose 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, Jagdish 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. 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.

Research

The first remarkable aspect of Jagadish Chandra Bose`s microwave research was that he reduced the waves to the millimetre level about 5 mm wavelength. That was within a few octaves of visible light. He knew that long waves were advantageous because of their great penetrative power but realised their disadvantages for studying the light like-properties of those electric waves. One year after Nikola Tesla made the first public demonstration of radio communication in 1893, Jagdish Chandra Bose ignited gunpowder and rang a bell at a distance using microwaves in wavelength in milimetre of range. This was held in a public demonstration in the Town Hall of Calcutta in November 1894, in the presence of Sir William Mackenzie, the Lieutenant Governor. Jagdish Chandra Bose wrote in a Bengali essay, `Adrisya Alok` (Invisible Light), "The invisible light can easily pass through brick walls, buildings etc. Therefore, messages can be transmitted by means of it without the mediation of wires." He can rightly be called the inventor of wireless telegraphy. Bose was the first in the world to fabricate and demonstrate in public this.

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." 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 (millimeter-wave) experiments to the Royal Institution and other societies in England. The wavelengths he used ranged from 2.5 cm to 5 mm. In his presentation to the Royal Institution in January 1897 Bose speculated 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 1.2 cm atmospheric water vapor absorption line was discovered during experimental radar work in 1944.


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.

His next contribution to science was in plant physiology. He forwarded a theory for the ascent of sap in plants in 1927. The ascent of sap is the upward movement of water from the root to the top in the transport tissues. According to his theory the pumping action of the living cells in the endodermis junction were responsible for the ascent of sap in plants. His research in plant stimuli were pioneering. He showed with the help of his newly invented `crescograph` that plants responded to various stimuli as if they had nervous systems like that of animals. He therefore found a parallelism between animal and plant tissues. His experiments showed that plants grow faster in pleasant music and its growth delayed in noise or harsh sound.

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