Inventing an intricate instrument, the "Resonant cardiograph," Bose then pursued extensive researches on innumerable Indian plants.
"Autobiography of a YOGI"
Paramhansa Yogananda
The cardiograph is constructed with an unerring accuracy by which a one-hundredth part of a second is indicated on a graph.
"Autobiography of a YOGI"
Paramhansa Yogananda