Quantity x = (Δ B/ B)  ·  (Δ t/Δ t ₀) ^−α has the pdf F( x) that is independent of Δ t, where Δ t ₀ ≈ 6.6 × 10 ³ s and α ≈ 0.46. The curves shown for Δ t ∈ {1, 4, 16, 64, 256, 1024} · 3 s are all in remarkable agreement with the lognormal distribution of μ = 0 and σ = 1, indicating that Δ B/ B is scale-invariant over the given values of x. For small Δ t, the agreement also extends far beyond the values of x shown, almost up to the cutoff at Δ B/ B = 2.