The invention of method for immediate record of growth and its
variations under various conditions is one of immense practical
importance. Experiments on gigantic scales are in progress all over the
world for this purpose. At Rothamstead, this work has been going on for
more than half a century. The great Department of Agriculture in
Mashington spends millions every year on such experiments, there being a
thousand men employed in research. Recently many experiments have been
undertaken on the effect of electricity on growth. The results obtained
have been mostly contradictory. For real advance in agriculture we must
first discover the laws of growth. Ordinary experiments on growth are of
little value because they take weeks for detecting changes of growth
which might have been brought about by charges in the environment. The
only satisfactory method is to devise an apparatus which would make the
plant itself record the rate of its growth, and the changes induced by
food or treatment in the course of less than a minute, during which
short time it is possible to maintain external conditions constant.