Most of these tropic movements are brought about by changes induced in
growth by the action of different forces. But growth is so excessively
slow that slight changes induced in it is impossible of detection. The
proverbially slow paced snail moves two thousand times faster than the
growing point of a plant. Hence to visualise growth and its changes,
apparatus has to be invented which would magnify growth something like a
million times. If such a thing were possible the pace of the snail
would be quickened to the speed of a rifle bullet. The difficulties in
connection with the devising and construction of apparatus with this
extraordinary power appeared at first an impossibility. The Jewels for
the fittings of the apparatus could not be found fine enough. The
lecturer had to discard ordinary jewels for diamonds, such bearings
being only made in Germany. But the outbreak of the war put an end to
this source of supply. He had then to turn to resources available in
India.