ICONISMUS II. illustration: A full-page scientific engraving illustrating the acoustics of a speaking trumpet or tuba stentorophonica. At the top of the diagram, a human head is shown in profile, blowing into the mouthpiece of a long, narrow conical instrument labeled "A".

The instrument extends vertically downward, widening gradually until it reaches a flared bell at the bottom, marked with points "C", "B", and "D". Inside the tube, a series of intersecting curved lines and nodes illustrate the reflection and propagation of sound waves. These nodes are labeled with a combination of Latin and Greek characters:

• Latin: A, R, Q, P, O, N, M, L, K
• Greek: γ, μ, τ, λ, ς, χ, θ, η, ψ, ε, δ, ζ, β
  Surrounding the instrument are large, concentric circular wave patterns representing the diffusion of sound into the ambient air. Several focal points of these external waves are labeled with capital letters: "H" and "I" on the upper sides, "E" and "F" on the lower sides, and "G" at the very bottom center. Small cross symbols (+) are positioned near the mouth of the bell at points C and D. The entire diagram is enclosed in a simple rectangular border.