The ‘Ectara.' by C. V. Raman (1909).

The ‘Ectara' by C. V. Raman (1909).

The “ectara.” A is the thick shell of a gourd that has been cut across in two places. Over the lower section is stretched a membrane M. A metallic wire S is attached perpendicular to the membrane at its center and kept stretched by a key.
(C. V. Raman, “The 'Ectara'” J Indian Math. Club 170-175 (1909), p. 443).