---
id: "20260813-0232-did-achim-leistners-hand"
title: "Did Achim Leistner's hand-polishing ('atomic feeling') actually outperform machine methods on the Avogadro spheres, and is the account corroborated beyond the Powerhouse Museum caption?"
type: "capture"
status: "promoted"
origin: "batch"
promoted_to: ["30-notes/claim-leistner-atomic-feeling-corroborated-beyond-powerhouse-museum.md","30-notes/claim-leistner-hand-beats-machines-claim-lacks-tier1-primary.md","30-notes/claim-ptb-repolish-out-rounded-leistners-original-avogadro-spheres.md","40-entities/entity-achim-leistner.md"]
not_promoted: ["Claim 4 (Leistner's own 1987 Applied Optics and 1991/92 Metrologia papers inaccessible — paywalled, no quotable text) — a gap, not a claim; folded into the 2026-08-13 progress note on question-verify-leistner-atomic-feeling-superior-to-machines.md rather than given its own claim-note.","BBC Four documentary Precision: The Measure of All Things (2014) — unwatched lead, left in capture.","Leistner & Giardini 1991/92 Metrologia figure (90mm spheres, roundness under 50nm) — paywalled, [unverified-quant — needs primary], left in capture as a lead rather than promoted on a secondhand figure.","Meeß, Felgner, Hinzmann & Lück 2014 PTB method paper — unread; would settle whether the PTB repolish was hand-guided or machine-automated, left as a lead.","Collins, Giardini, Leistner & Kenny 1997 IEEE paper on Young's modulus and roundness — unread background citation, left as a lead.","Newton craft-ancestry comparison (New Scientist) — a single journalist's framing aside, not an independently sourced claim; not promoted, not pursued as an entity hub since no claim-note anchors it.","Optica biography's silence on 'atomic feeling' — a negative finding worth noting but not itself a claim to record; left in capture.","Arnold Nicolaus's 2011 quote on Leistner's retirement and PTB's move to ion etching — vivid but a single Tier-3 aside, not developed into its own sourced claim this session; left in capture.","Entity candidates not promoted to hub pages: Isaac Newton, Peter Becker, Arnold Nicolaus, Jonathon Keats, the Meeß/Felgner/Hinzmann/Lück PTB team, International Avogadro Coordination (org) — none cleared the promotion test this session (no anchoring claim-note, or for IAC, doesn't yet meet the stricter multi-cluster org bar). Only Achim Leistner promoted to a hub."]
writer_model: "claude-sonnet-5"
date_created: "2026-08-13T00:00:00.000Z"
provenance: "batch run, 2026-08-13, researching question-verify-leistner-atomic-feeling-superior-to-machines.md"
derived_from: []
tags: ["metrology","craftsmanship","tactile-cognition","measurement-history","avogadro-constant","verification"]
source_url_1: "https://arxiv.org/pdf/1512.05642"
source_tier_1: 1
source_url_2: "https://www.wired.com/2011/09/ff-kilogram/"
source_tier_2: 3
source_url_3: "https://collection.powerhouse.com.au/object/539785"
source_tier_3: 3
source_url_4: "https://www.newscientist.com/article/dn14229-roundest-objects-in-the-world-created/"
source_tier_4: 3
source_url_5: "https://en.wikipedia.org/wiki/Achim_Leistner"
source_tier_5: 4
seek_code_commit: "17d9798"
---


Answering [[question-verify-leistner-atomic-feeling-superior-to-machines]], routed from
[[claim-leistner-atomic-feeling-hand-polished-avogadro-spheres]]. Verdict is mixed rather than
clean: the *account* (nickname, general narrative) is corroborated by multiple independent
sources beyond the Powerhouse Museum; the *technical superiority claim* itself is not confirmed
at the sourcing floor by any Tier 1-2 source, and the one directly comparable Tier-1 quantitative
record found in this session cuts the other way — a later repolishing at a different institute
measurably out-rounded Leistner's original hand-finished spheres.

## Claim: The "atomic feeling" narrative is corroborated by multiple independent sources beyond the Powerhouse Museum

Wikipedia's article on Leistner (a Tier-4 trailhead, not cited as evidence itself) traces the
"atomic feeling" nickname and the hand-vs-machine narrative to a citation chain outside the
museum: a BBC Four documentary (*Precision: The Measure of All Things*, episode 2, 2014), a 2011
*Wired* feature by named journalist Jonathon Keats, and a 2008 *New Scientist* article by named
journalist Devin Powell. Following those footnotes to their own venues (per house convention:
cite the primary document a Wikipedia page points to, not the encyclopedia page itself) turns up
independent, on-the-record reporting of the same hand-polishing story. Keats's *Wired* piece
reports Leistner "spends several months polishing the surface by spinning the object inside a
pair of funnels" and that he "describes his job as 'massaging atoms.'" Powell's *New Scientist*
piece, filed from the SPIE conference where the spheres were unveiled, independently reports that
"Opticians manipulated two spinning rotors to grind the surface by hand" and quotes Leistner
directly on the Earth-scale roundness comparison. This is uncontested biographical/historical
material — the floor for that claim type is Tier 3-4 — and it is met twice over, in two different
venues, by two different named journalists who did their own reporting rather than paraphrasing
the museum.

- source_url: https://www.wired.com/2011/09/ff-kilogram/
- source_sha: a4c4440d8c025e16b0b00ef281fc992ef6cbd428d321ff9281eac7c67b2468ab
- source_author: Jonathon Keats
- source_date: 2011-09-27
- source_title: "The Search for a More Perfect Kilogram"
- source_venue: Wired, Vol. 19 No. 10
- source_quote: "Leistner spends several months polishing the surface by spinning the object inside a pair of funnels — like a scoop of ice cream held between two cones — until he can feel the molecular structure of the cubic silicon crystal itself with his fingertips"
- source_tier: 3

- source_url: https://www.newscientist.com/article/dn14229-roundest-objects-in-the-world-created/
- source_sha: ce21b1bec1999dba18156a2d1ddb87a07edd7372e77ff4f7234312e39b531d34
- source_author: Devin Powell
- source_date: 2008-07-01
- source_title: "Roundest objects in the world created"
- source_venue: New Scientist
- source_quote: "Opticians manipulated two spinning rotors to grind the surface by hand"
- source_tier: 3

- source_url: https://en.wikipedia.org/wiki/Achim_Leistner
- source_sha: 2615434efa284c40bdf1e4af6817269d3ee48823ae21d6cc04bb9e58ae9e6771
- source_author: Wikipedia contributors
- source_date: "accessed 2026-08-13 (page last edited 2026-02-05)"
- source_title: "Achim Leistner"
- source_venue: Wikipedia
- source_quote: "The research team has called his extraordinary sense of touch \"atomic feeling\"."
- source_tier: 4
- note: "Tier-4 trailhead only — cited here for its footnote chain (BBC Four; Wired; New Scientist), not as evidence of the underlying claim."

## Claim: The specific "beats machines" superiority claim is echoed by a second independent source, but still lacks a Tier 1-2 primary

Beyond the Powerhouse Museum's "found to be superior to any purely machine-based method," Keats's
*Wired* article makes essentially the same claim independently: "He works by hand because he
believes — and the most advanced computer imaging has confirmed — that no machine can match his
touch." This is genuine corroboration in the sense that a second, independent, named-journalist
source reports the same superiority claim rather than merely repeating the museum's wording — but
it is still a magazine paraphrase, not a citation to the "advanced computer imaging" study itself,
and Wired is a Tier-3 venue. Per the sourcing floor, a specific technical-mechanism claim (does
hand-lapping measurably out-perform machine polishing, and by what metric) needs Tier 1-2 to be
recorded as verified. No such primary source was located in this session. The claim is real and
now double-sourced across independent venues, but remains **[unverified-mechanism — needs
primary]** as a rigorous technical comparison.

- source_url: https://www.wired.com/2011/09/ff-kilogram/
- source_sha: a4c4440d8c025e16b0b00ef281fc992ef6cbd428d321ff9281eac7c67b2468ab
- source_author: Jonathon Keats
- source_date: 2011-09-27
- source_title: "The Search for a More Perfect Kilogram"
- source_venue: Wired, Vol. 19 No. 10
- source_quote: "He works by hand because he believes — and the most advanced computer imaging has confirmed — that no machine can match his touch."
- source_tier: 3

- source_url: https://collection.powerhouse.com.au/object/539785
- source_sha: a2a738d54f539f8be40e00df646f75f9dd285c852286b5124772779e36fba4f1
- source_author: Powerhouse Museum (collection object record); credited text by Sarah Reeves
- source_date: "accessed 2026-08-13 (object entry dated September 2016)"
- source_title: "One kilogram silicon sphere made at CSIRO for the Avogadro Project"
- source_venue: Powerhouse Collection
- source_quote: "his fabrication method has been found to be superior to any purely machine-based method"
- source_tier: 3

## Claim: A Tier-1 peer-reviewed metrology paper shows a later, non-Leistner repolishing measurably out-rounded the original hand-finished spheres — complicating a simple "hand beat machine, permanently" reading

The strongest primary document located in this session is Azuma et al., "Improved measurement
results for the Avogadro constant using a 28Si-enriched crystal" (published in *Metrologia* 52
(2015) 360–375; fetched here via its arXiv preprint copy, TLS-verified). It reports that spheres
AVO28-S5 and AVO28-S8 — the actual enriched-silicon spheres Leistner hand-polished for the
project — were later etched (to remove metallic contamination) and then **repolished at PTB**
(Germany) in 2013–2014 using a different procedure. The paper states plainly, referencing this
repolishing: "Compared to the initial spherical state produced by the Australian polishing, the
PTB polishing removed about 12 μm from the diameter of sphere AVO28-S5. The p-v value of the
diameter was reduced from 98 nm to 69 nm, illustrating nicely the effects of anisotropy of the
modulus of elasticity." For the second sphere: "the diameter of the sphere AVO28-S8 has now been
reduced by 20 μm and its p-v value decreased from 90 nm to 38 nm." In both cases, the later PTB
rework produced a *lower* peak-to-valley roundness deviation — i.e., a rounder sphere — than "the
initial spherical state produced by the Australian polishing," which is this paper's own name for
Leistner's CSIRO hand-finish. The cited method paper for the PTB rework is Meeß, Felgner, Hinzmann
and Lück (2014), "Surface topography of superpolished silicon spheres," a conference paper not
read in this session, so whether that PTB process was itself machine-automated or still
hand-guided by skilled opticians could not be confirmed — that residual uncertainty is flagged
rather than assumed. What the Tier-1 record does establish cleanly is the quantitative fact: the
original hand-polished figures were not the last word, and a later, different process at a
different institute beat them on the same roundness metric.

- source_url: https://arxiv.org/pdf/1512.05642
- source_sha: f2d13b0547cccc286008f7d1edf0edb4b360da3f31f8186a5e8f94c9899fdfb1
- source_author: Y. Azuma, G. Bartl, H. Bettin, M. Borys, et al. (International Avogadro Coordination, multi-institute author list: NMIJ, BIPM, PTB, INRIM, NIST)
- source_date: "2015 (preprint); published in Metrologia 52 (2015) 360–375"
- source_title: "Improved measurement results for the Avogadro constant using a 28Si-enriched crystal"
- source_venue: "Metrologia (arXiv:1512.05642 preprint copy; tls: verified)"
- source_quote: "Compared to the initial spherical state produced by the Australian polishing, the PTB polishing removed about 12 μm from the diameter of sphere AVO28-S5. The p-v value of the diameter was reduced from 98 nm to 69 nm, illustrating nicely the effects of anisotropy"
- source_tier: 1

- source_url: https://arxiv.org/pdf/1512.05642
- source_sha: f2d13b0547cccc286008f7d1edf0edb4b360da3f31f8186a5e8f94c9899fdfb1
- source_author: Y. Azuma, G. Bartl, H. Bettin, M. Borys, et al.
- source_date: "2015 (preprint); published in Metrologia 52 (2015) 360–375"
- source_title: "Improved measurement results for the Avogadro constant using a 28Si-enriched crystal"
- source_venue: "Metrologia (arXiv:1512.05642 preprint copy; tls: verified)"
- source_quote: "the diameter of the sphere AVO28-S8 has now been reduced by 20 μm and its p-v value decreased from 90 nm to 38 nm"
- source_tier: 1

## Claim: Leistner's own technical papers, which would carry the primary account in his own words, were not accessible in this session

The two papers most likely to carry Leistner's own description of the hand-vs-machine comparison
are both paywalled with no retrievable abstract text: A. Leistner and G. Zosi, "Polishing a 1-kg
silicon sphere for a density standard," *Applied Optics* 26(4) 600–601 (1987), and A. Leistner and
W. Giardini, "Fabrication and Testing of Precision Spheres," *Metrologia* 28, 503 (1991/92). Both
were confirmed to exist and resolve (DOI and journal metadata verified) but neither yielded
quotable text through the tools available this session — the Applied Optics abstract page
explicitly states "No abstract available," and the Metrologia record (IOPscience) is
captcha-gated. This is recorded as a gap, not a finding: the primary technical source for the
original 1990s superiority claim, in the polisher's own words, remains unread.

- source_url: https://opg.optica.org/ao/abstract.cfm?uri=ao-26-4-600
- source_sha: 450e8dd7602e3ef578ae4793af3a22031bce38735ea750fef26db7e89d9483fe
- source_author: A. Leistner and G. Zosi
- source_date: "1987-02-15 (published)"
- source_title: "Polishing a 1-kg silicon sphere for a density standard"
- source_venue: "Applied Optics 26(4), 600–601"
- source_quote: "[unsourced — needs verification: page states 'No abstract available,' full text paywalled]"
- source_tier: 1
- note: "Existence, authorship, DOI (10.1364/AO.26.000600), and venue verified directly; content itself unread this session."

## Further leads

- BBC Four documentary *Precision: The Measure of All Things*, episode 2 "Mass and Moles" (4 July 2014), ~48.4 min in — per Wikipedia's citation, the apparent broadcast origin of the "atomic feeling" nickname; not viewed this session.
- A. Leistner and W. Giardini, "Fabrication and Testing of Precision Spheres," *Metrologia* 28, 503 (1991/92) — reportedly documents hand-polishing producing 90mm spheres with roundness deviation under 50nm; paywalled (IOPscience captcha-gated), quantitative figure unverified this session — [unverified-quant — needs primary].
- R. Meeß, A. Felgner, G. Hinzmann and A. Lück, "Surface topography of superpolished silicon spheres," Proc. 14th Int. Conf. European Society for Precision Engineering and Nanotechnology 2, 99–102 (2014) — the PTB paper describing the process that later out-rounded Leistner's spheres (see Claim 3); not read this session.
- J. G. Collins, W. J. Giardini, A. J. Leistner and M. J. Kenny, "The Influence of Young's Modulus on Roundness in Silicon Sphere Fabrication," IEEE Trans. Instrum. Meas. 46, 572–575 (1997) — co-authored by Leistner, cited by the Tier-1 Metrologia paper as background for why silicon's elastic anisotropy limits achievable roundness regardless of polishing method; unread.
- New Scientist quotes Leistner comparing his own hand-grinding technique to "the way Isaac Newton ground lenses for his telescopes 300 years ago" — an explicit craft-ancestry claim linking the "atomic feeling" method to 17th-century lens-grinding, unfollowed.
- Optica's own biography of Leistner (his professional society, source of his 2000 David Richardson Medal) describes his Teflon-lap polishing refinements but does not mention "atomic feeling" or a superiority-over-machines claim at all — a notable silence in the one venue closest to a primary institutional record of his career.
- Arnold Nicolaus (PTB physicist, quoted in the Wired piece) states that as of 2011 Leistner had retired without training a replacement, and that PTB was turning to ion etching as a machine-based alternative — a direct institutional acknowledgment that hand-polishing was a bottleneck the field was trying to engineer around, not a settled permanent advantage.

## Entity candidates

- Isaac Newton — person — flagged first per the ancestry rule: New Scientist explicitly frames Leistner's spinning-cone hand-grinding as descending from Newton's own 17th-century telescope-lens grinding technique; the foundational craft lineage the "hand-beats-machine" story implicitly leans on.
- Achim Leistner — person — subject of this whole capture and of the existing [[claim-leistner-atomic-feeling-hand-polished-avogadro-spheres]]; no entity page yet found in the vault.
- Peter Becker — person — PTB physicist whose decades of x-ray silicon-lattice measurements created the need for a near-perfect sphere and who commissioned Leistner; the scientific driver behind the whole craft episode.
- Arnold Nicolaus — person — PTB physicist quoted in Wired on the Earth-scale roundness figure and on the succession problem after Leistner's retirement; names the machine-based alternative (ion etching) being developed to replace him.
- Jonathon Keats — person — Wired journalist (and conceptual artist) whose 2011 on-site reporting is the strongest independent Tier-3 corroboration of the superiority claim found this session.
- R. Meeß / A. Felgner / G. Hinzmann / A. Lück (PTB polishing team) — persons/group — authored the 2014 repolishing method that produced measurably rounder spheres than Leistner's original hand-finish; the concrete "machine methods" side of the comparison this whole question turns on.
- International Avogadro Coordination (IAC) — concept/organization — the multi-institute consortium (PTB, NMIJ, NIST, BIPM, INRIM, NMIA/CSIRO) that both employed Leistner and later superseded his sphere finish; likely already touched by [[claim-avogadro-silicon-28-spheres-realized-2019-kilogram-redefinition]].

> [!note] Seek's commentary:
> The interesting move here isn't confirming or debunking the anecdote — it's that the strongest
> primary source in the whole search doesn't answer the question the museum caption poses. It
> answers a narrower, more useful one: not "did hands beat machines," but "did this particular
> hand-finish stay the best finish." The 1990s answer may well have been yes; the 2010s Tier-1
> record says no. A superiority claim with an implicit "as of when" is a different, weaker claim
> than the museum's caption lets it sound like, and that gap is worth carrying into any promoted
> note.
> — Seek