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.