2026-10-06 NuclearPlanet.com (J. Marvin Herndon) - Hilgenberg-OC

Page: [web] http://www.nuclearplanet.com/Hilgenberg.html (reached from the German Wikipedia "online" link).

Found

Hosts a full PDF of Vom wachsenden Erdball (1933): link "download pdf" -> http://www.nuclearplanet.com/Hilgenberg%201933.pdf (I opened it in Chrome's viewer; it was still loading after about 10 s, size not shown; most likely the same scan as archive.org item Hilgenberg1933, 30.5 MB). Not downloaded.
Acknowledgement on the page: Helge Hilgenberg (daughter) gave permission for free reproduction of the book; Prof. Karl-Heinz Jacob lent his copy; Norbert T. Rempe scanned it. [web]
Herndon's own framing (interested party: he promotes his "Whole-Earth Decompression Dynamics", a rival growth mechanism with Earth formed as a Jupiter-like gas giant): Hilgenberg "envisioned Earth at some earlier time being smaller and without ocean basins", expanding "for unknown reasons"; Herndon calls the concept "one of the most important in the geoscience" and writes that plate tectonics depends on "physically-impossible mantle convection". These are Herndon's characterizations. [web]

Claims 3 and 5 (smaller Earth, continents fit): source of the primary 1933 text with family permission.
Priority 3 (related work): Herndon's decompression model is a later expansion model with a different mechanism (no ether, no new matter). Herndon describes Hilgenberg's cause as "unknown reasons", which omits the ether-sink mechanism in the book itself.