Kennard: Investigator site log

Run 1: 2026-10-04 (first run, no earlier sites.md). Chrome-based. Web time was capped at 10 min; searching stopped at about 7 min (timer 1791152385 to about 1791152800), when the most productive leads were in hand. Notes are in research/2026-10-04-*.md and downloads in research/files/.

Keywords tried

G1 "Kennard" "unipolar induction" 1917 OR 1912 OR 1913 Philosophical Magazine OR "Physical Review" G2 site:archive.org Kennard "unipolar induction" G3 "Earle Hesse Kennard" OR "E. H. Kennard" physicist Cornell Minnesota biography obituary G4 "Electrodynamics of Moving Media" 1922 Kennard Swann "National Research Council" bulletin unipolar G5 "Kennard" "Barnett" rotating condenser solenoid unipolar induction experiment aether history G6 "crossref-pre-1923" "unipolar induction" OR "physrev.1.355" OR "14786440608637294" OR "physrev.10.591" G7 archive.org "philosophical magazine" "6th ser." "v. 23" 1912 G8 Pegram 1917 "Unipolar induction and electron theory" Physical Review pdf G9 "One century later" "Remarks on the Barnett experiment" OR "Unipolar induction: a case study of the interaction between science and technology" G10 (Books) "Kennard" "unipolar induction" aether 1912..1925 G11 site:conservancy.umn.edu OR site:umn.edu Kennard physics 1915 OR 1916 Erikson "unipolar" OR "Kennard" instructor G12 "Kennard" University of Minnesota physics 1914 1916 "Erikson" unipolar OR "rotating condenser" archive.org API: creator:(Kennard) AND (title:unipolar OR title:induction OR title:dielectrics OR title:aether); title:(unipolar induction); title:(effect of dielectrics on unipolar); title:(Kennard) AND title:(rotating); title:(philosophical magazine) AND date:[1912] Crossref: query.author=Kennard, until 1925. Semantic Scholar: citations of the 1917 DOI; search XCIII Unipolar induction Kennard-Bartlett (429). arXiv: ti:"unipolar induction", au:Chyba_C. scholar.archive.org: "unipolar induction" year:[1900 TO 1925]. Follow-up Q14 (2026-10-08): F14-1 homopolar generator "rotating magnet" field does not rotate Faraday 1832 Kennard Pegram practical design brushes; F14-3 DePalma N-machine one-piece Faraday generator magnet rotating with disk back torque tests Kincheloe Stanford; F14-5 homopolar motor reaction torque acts on external circuit not magnet experiment Guala-Valverde OR "return path" unipolar; F14-7 superconducting homopolar motor navy ship propulsion General Atomics liquid metal current collectors challenges; F14-8 "unipolar induction" Miller "Frontiers of Physics" Faraday Kennard Barnett Pegram "lines of force" rotate. Wikipedia raw pages Homopolar_generator, Faraday_paradox. Not yet tried (next run): "Kennard" "Townsend" Oxford 1911 1912 unipolar; "Unipolarinduktion" Kennard / Barnett / Fehrle (German); "induction unipolaire" Kennard (French); "Christian Dane" mechanician Minnesota; "Henry A. Erikson" Minnesota physics; "Kennard" "ether" 1922 NRC "moving media"; Kennard obituary 1968 Physics Today; "Kennard" gyrocompass "absolute rotation" ether; "homopolar" Kennard condenser; "Wijngaarden" comment Chyba 2026.

Leads for review

1. The inventor's own work

• Kennard's own Faraday disk (follow-up Q14). The 1917 apparatus carried "a Faraday disk A ... mounted on the end of the shaft" whose galvanometer reading was proportional to field times speed [read: _text p.4]; the electrometer/galvanometer ratio is an open-circuit charge divided by a closed-circuit Faraday-disk current. Kennard 1912 states that closed circuits cannot decide the seat of the EMF in Faraday's rotating-magnet experiment. Bears on claims 1-3 and 5.
• Kennard 1912, "Unipolar Induction", Phil. Mag. (6) 23, 937-941 (full text: research/files/Kennard-1912-PhilMag-23-937-Unipolar-Induction_IA-OCR.txt) [web] https://archive.org/details/londonedinburg6231912lond. Oxford work under J. S. Townsend. A steel magnet bar was rotated inside a stationary solenoid, with an electrometer on an outer cylinder screened by an earthed case. Observed 0.0 ±0.24 divisions against a moving-line prediction of about 37 (at least 26). Kennard concludes "a rotating magnet does not 'carry its force lines' around with it", and induction "depends on absolute motion--that is, on motion relative to the ether". He states that the method cannot separate Lorentz from Hertz. Bears on claims 5 and 6, and on the "1912 negative result" background in the 1917 paper. The 1912 paper already contains the Laplace's-equation argument of 1917 §7.
• 1917 pp.188-190, cleaner text (research/files/Kennard-1917-PhilMag-33-179-IA-OCR.txt): this closes the gap where claims 5-6 rested on the digest alone. The §7 equations are readable. §8 adds the gyrocompass analogy for "absolute rotation" and openly allows "Rotation relative to the earth might in some unknown way be responsible ... but this seems improbable". It calls the effect "perhaps, the only low-frequency phenomenon which cannot easily be described in terms of 'action at a distance' between electrons and atoms". Bears on claims 5 and 6.
• Kennard 1913, "The Effect of Dielectrics on Unipolar Induction", Phys. Rev. 1, 355-359 (DOI 10.1103/PhysRev.1.355), and Phys. Zeits. 13, 1155 (1912); 14, 256 (1913): Kennard's three replies to Barnett, the "fully discussed elsewhere" of 1917 §7. Not yet obtained. Bears on claim 5.
• NRC Bulletin "Electrodynamics of Moving Media" (1922), co-authored by Kennard (HathiTrust full view). This is his post-1917 position on moving media. It is the key record for whether he kept the stationary-aether reading. Bears on claim 6.
• AIP Niels Bohr Library, Kennard Papers AR 176: reprints 1912-1928 (Box 10 F3) and Cornell E&M lecture notes 1926 (Box 4 F4). Bears on claim 6 (later views) and the historical record.
• Other Kennard items of the period (name match only, not opened): Science 43, 928 (1916) "Electrical Action and the Gravitation Constant"; Science 47, 271 (1918) "Note on Three Devices for Use in Electrometry".

2. Supporting information by others

• Faraday 1832 (Arts. 217-227) and 1851 (Arts. 3090-3118), via McDonald (follow-up Q14): rotating magnet with stationary wires gives current; wires rotating about a resting magnet gives current; both together gives none; Art. 3118 "(re)affirmed that magnetic field lines do not rotate with a rotating magnet" (McDonald's words). Closed-circuit precursors of Kennard's claims 3 and 5; Faraday's text not read directly.
• S. J. Barnett, "A Report on Electromagnetic Induction", Trans. AIEE 1919 (research/files/AIEE-1919-report-electromagnetic-induction.pdf). Barnett, Kennard's critic, says his "corollary ... has been confirmed in each of two recent investigations; one by Kennard ... and one by Pegram ... The condenser was found to become charged in accordance with the theory." He adds that the experiments "prove either (1) that the ether does not exist and that the tubes of induction do not move, or (2) that the ether exists." This is independent acknowledgement of claims 1-3. On claim 6 it is a two-way reading: Barnett does not endorse the aether conclusion but leaves it as one of two options.
• G. B. Pegram, "Unipolar Induction and Electron Theory", Phys. Rev. 10, 591 (1917): an independent experiment with condenser and coil rotating together, giving charging (per Barnett 1919 and Chyba 2025). PDF not obtained (SciSpace blocked; McDonald copy 401). Bears on claims 1-3.
• Chyba, Hand & Chyba 2025, Phys. Rev. Research 7, 013285 (PDF saved). Their summary: the Barnett/Kennard/Pegram results "proved that the field of a rotating axially symmetric electromagnet does not 'rotate with the magnet,' a conclusion that is now a standard part of the electromagnetics literature." This supports Kennard's experimental claims (1-3 and the "lines do not rotate" part of 5) as accepted. The same authors read v in v x B as relative to the observer's frame, not an aether (their characterization), which bears against the interpretive claim 6. They credit the corotation result to Pegram only; Barnett 1919 credits Kennard too.
• Barnett 1922, Phil. Mag. "CIII. Electric fields due to the motion of constant electromagnetic systems" (DOI 10.1080/14786441008634077), which cites Kennard 1917. Not opened.

3. Closely related work

• Homopolar machines in practice (follow-up Q14): one-piece magnet-plus-disk rotors (Delafield US 278516, Tesla US 406968, Noeggerath, Forbes dynamo); ANU 500 MJ / 2 MA pulsed generator 1962-1986; Parker Kinetic Designs railgun supplies; General Atomics superconducting homopolar motors for the Navy (500 kW, 3.7 MW); liquid-metal current collectors (Eriksson 1982). Practical consequence of the non-rotating field: magnet may rotate with the rotor, but a stationary return path with sliding contacts is unavoidable.
• Guala-Valverde, Mazzoni & Achilles 2002, Am. J. Phys. (follow-up Q14; saved): torque experiments locating the reaction between magnet and closing wire; classify Kennard as "absolutistic" and adopt a relational (Weber/Assis/Kelly) framework (their characterization). Bears on claim 6.
• DePalma N-machine and Kincheloe's 1986 test (follow-up Q14): DePalma (inventor, interested party) claimed the one-piece machine's reaction torque is "not reflected back to the mechanical driving source"; Kincheloe (Stanford EE emeritus) found it "did not perform as claimed" but reported "repeatable data showed anomalous results that did not seem to conform to traditional theory". Bears on claim 6 (absolute vs relative rotation) as related work.
• Wikipedia "Faraday paradox" (follow-up Q14): says electrostatic tests of field rotation "apparently" have not been performed (citation needed); contradicted by Kennard 1912/1917, Pegram 1917 and Barnett 1919. A stale secondary claim worth noting for readers.
• Weber/Ampère and "Galilean" electrodynamics treatments of unipolar induction that cite Kennard 1917: J. P. Wesley (1990 Found. Phys. Lett. "Weber electrodynamics, part II unipolar induction, Z-antenna"; 1997 "Empirically correct electrodynamics"); Assis & Thober 1994; Wilhelm 1994; Bartocci & Capria 1991. They share Kennard's view that the open-circuit results are not trivially relativistic. They are often labelled fringe by mainstream sources; that label is a characterization, and the works are kept here as related.
• Spinning-magnet line: Bartlett, Monroy & Reeves 1977 Phys. Rev. D; Guala-Valverde 2002 Physica Scripta "Spinning magnets and relativity: Jehle vs. Bartlett"; Montgomery 2007 comments; Djurić 1975; Müller 2014 IEEE TMAG ("edge effect" theory with new experiments); Chen et al. 2017; Baumgärtel et al. 2021-2022 (PDF saved; "Kennard's, Bartlett's and Barnett's experiments" discussed under Ampère-force explanations). An unidentified abstract on Semantic Scholar claims experiments that "categorically disprove absolutistic Kennard-Bartlett-type interpretations". That is the source's characterization; the paper is not yet identified.
• Kholmetskii 2003, Am. J. Phys. 71, 558 "One century later: Remarks on the Barnett experiment" (+ erratum), and C. C. Su 2005 arXiv physics/0512179 (saved). Su discusses Kennard 1912 and 1917 and argues a short solenoid's nonuniform field could induce an EMF in Kennard's outside-capacitor arrangement. These are modern re-analyses. Chyba says an "attempted theoretical refutation" was "shown to be incorrect due to calculational error"; which papers it means is unverified.
• Earth-rotation power generation (Chyba & Hand 2016; Chyba et al. 2025; Veltkamp & Wijngaarden null result; Wijngaarden 2026 Comment): the same principle (a conductor moving through an axisymmetric field that does not co-rotate) applied to a claimed energy source. Contested.
• NASA Breakthrough Propulsion Physics (Millis 1996, saved) cites Kennard 1917 in a Mach's-principle and space-drive context. Bears on claim 6 (absolute rotation).
• McDonald, "Is Faraday's Disk Dynamo a Flux-Rule Exception?" (saved, 131 pp). A historical bibliography of the 1910s-1920s debate: Barnett, Kennard, Wilson & Wilson, Blondel, Howe, Pegram, Swann, Tate. Tate (1922) is called "a useful review".

4. Historical record

• Biography (AIP finding aid): Rhodes Scholar at Oxford (B.S. 1911), where the 1912 experiment was done under Townsend. Ph.D. Cornell 1913. Instructor at the University of Minnesota 1914-1916, where the 1917 experiment was done (acknowledging Henry A. Erikson and mechanician Christian Dane). Cornell professor from 1926; US Navy David Taylor Model Basin 1941-1960 (hydrodynamics, underwater explosions, ship vibration); died 1968. Bears on context, and on the "absence of evidence" question below.
• Absence of evidence: Kennard's unipolar/aether line ends in 1917. After the 1917 paper no further unipolar experiments by Kennard were found. He moved to the 1922 NRC moving-media report, then quantum mechanics (Z. Phys. 1927), kinetic theory and Navy work. Competing explanations: (a) the experimental question was considered settled; even his critic Barnett accepted the result by 1919; (b) the condenser-alone run ended when the solenoid short-circuited and "it was not thought worth while to rewind it" (1917 p.9), and he left Minnesota in 1916; (c) the field moved on to relativity and quantum theory, so an aether interpretation stopped being publishable or interesting; (d) he changed his view. Records that would decide: his 1922 NRC chapter, the 1926 Cornell E&M lecture notes (AIP Box 4 F4), and the Cornell memorial statement.
• The Barnett-Kennard dispute, 1912-1913 (Barnett 1912 and 1913, saved). Barnett calls Kennard's 1912 work "inconclusive" and "based on incorrect theory", and says "Mr. Kennard's fallacies are quite apparent". These are the characterizations of a direct scientific rival. His specific objection is that in 1912 only the iron core rotated while the magnetising coil stayed fixed, so one cannot say what fraction of the "lines" would move. Kennard's 1917 design (solenoid itself rotatable) answers this directly. Bears on claims 1, 3 and 5.
• Rapid international uptake: the 1917 paper was abstracted in Jahrbuch der Radioaktivität und Elektronik (1917) p.377 and in Fortschritte der Physik / Verh. DPG 19 (1917) p.110 [web] Google Books snippets. It was cited in a 1924 University of Wisconsin engineering B.S. thesis on unipolar induction (Google Books KalsAAAAMAAJ, full view, not yet read).