An Apparatus-Associated Tuning Attractor in Tesla's Colorado Springs Experimental Records (1899): Sequential Structure Analysis of the Chronological Notebook Sequence

This report presents a sequential structure analysis of Nikola Tesla's Colorado Springs laboratory notebook (June 1899 – January 1900). Two principal findings are reported. First, Tesla's October 1899 apparatus-tuning sequence converges to a statistically confirmed attractor at 141.6 ± 3.5 Hz (CV = 0.025), classified as statistically confirmed under matched-length null calibration across three independent random seeds (structural score = 0.514, z = +16.0 for the October subset; structural score = 0.300, z = +2.5 for the full Type A trajectory). The finding is robust to ±5% frequency perturbation (100% survival rate, 1000 trials) and stable under leave-one-out sensitivity testing (8 of 9 sessions). Second, the full campaign Hurst exponent H = 0.845 demonstrates persistent long-range memory across Tesla's parameter choices — the mathematical signature of structured experimental search rather than random trial-and-error. A notation audit confirms that Tesla's September–October entries record angular frequency (rad/s); all values are presented as converted cyclic frequency f = w/2pi in Hz. The analysis formally separates Tesla's Type A coil-tuning parameters from his Type B terrestrial-resonance reasoning, identifying a category error in the standard engineering critique of his Earth-resonance claims. The 141.6 Hz attractor is evanescent in the Earth-ionosphere waveguide (first-mode cutoff approximately 1,600-1,800 Hz) and is interpreted as an apparatus-local resonance.