Excerpt from Variation in Pitch Discrimination Within the Tonal Range (Classic Reprint)
The sounder was a simple device consisting merely of a lead pipe about one inch in diameter with one end bent into the form of a circle for the base, and the other in the shape of a U at right angles to the base. The U — end, when covered with several thick: nesses of rubber, made a sounder of the required elasticity and softness. The placing of the sounder on leather sand-bags resting on a heavy metal stand eliminated, in large part, the accessory noise of the blow. The forks of the four central octaves were energized by striking the middle of the prong upon the sounder; the forks of 2048 v.d. Were struck as lightly as possible with a felt-hammer; while those of 64 v.d. Were set into vibration by striking them on the sand-bags.