US 197148

I'll run targeted searches before summarizing.

Search result summary

Identification confirmed. A search of patent literature and Federal Circuit materials returns exactly one document matching the literal string 197148 in the pre-1900 US patent series: US 197148 A, "Improvement in amalgamating-pans." All other hits for "197148" are unrelated identifiers — e.g., WO 2024/197148 (cyclic structured oligonucleotides), WO 2016/197148 (cleaning formulations), CAFC No. 26-1485 (Clear Imaging Research v. Google), U.S. Serial No. 197,148 in US 2,235,878 (cushion construction, filed 1938). None of these is US 197,148 and none should be conflated with it.

CAFC 2026 dockets: No 2026 Federal Circuit docket involves this patent. This is expected — the patent issued in 1877, expired in 1894, and the CAFC did not exist until 1982. I found no CAFC, district court, or PTAB activity, and no reissue or reexamination record. If you need authoritative negative confirmation you should query the CAFC docket system (fedcourt.gov / CM-ECF) and USPTO Patent Public Search directly; my searches were web-based only.

---

Bibliographic data — US 197,148 A

Uncertainty note on dates: Google Patents' structured "prior art date" field also shows 1877-11-13, which conflicts with the specification's express statement that the application was filed August 21, 1877. I treat the specification's filing date as authoritative and the structured field as a data-field artifact. I cannot verify the original USPTO filing receipt independently.

---

Abstract

There is no abstract. US 197,148 issued in 1877, decades before abstracts became a required part of US patent specifications (the abstract requirement dates to the 1952 Patent Act). Any "abstract" text on a modern database page is a machine-generated summary, not part of the original document. The closest thing to an abstract is the specification's statement of invention:

"Our invention consists in constructing an amalgamating-pan in the form of a circular sluice, and providing one or more pools of quicksilver at one end of the sluice, over which the ore-pulp is compelled to travel, while the remainder of the pan or sluice bottom is covered with amalgamated-plates. A semi-rotary vibrating motion is imparted to the pan, so that the particles of pulp are sifted over the mercury and amalgamated surfaces, so as to settle them to the bottom, and cause them to become amalgamated."

---

Plain-language overview of the disclosure

The device is a gold/silver ore amalgamator built as a circular trough (sluice) rather than a straight one. A flat-bottomed annular channel is bounded by an outer rim H and an inner rim R; the bottom P is covered with overlapping amalgamated copper plates. The whole pan A is carried on a central upright spindle C, cross-braced by radiating arms B B and capped by an arched yoke D, so the pan can swing rotationally about its center.

Pulp is fed into the trough at one side of a full-height radial partition E, must travel the entire circumference, and exits through a discharge opening F in the bottom on the opposite side of the partition — so residence time on the amalgamating surface is long, packed into a small footprint ("a great length of amalgamating surface in a small compass").

Near the feed point, shallow cross-bars G G create one or more recesses X filled with quicksilver, which the pulp must traverse. Downstream of that series, a cavity I with an inclined bottom (its low end against the last bar, its high end against the second-to-last) forms a quicksilver trap to catch mercury trying to escape with the tailings.

Motion is supplied by a driving shaft J carrying a crank L linked by a pitman K to the pan, producing a quick semi-rotary horizontal oscillation (back-and-forth rather than continuous rotation). The specification states this sifting/oscillating action is what settles and amalgamates the heavy particles and distinguishes the results obtained ("a peculiarly-effective motion").

The specification also notes (in a truncated passage: "A longitudinal sluice can also be constructed…") that the same arrangement can be built as a straight sluice — i.e., the inventors contemplated a linear variant of the same concept.

---

Claims

The patent has two claims. Both are written in the old "substantially as and for the purpose described" style with element-by-letter references. Important caveat: the claim text as retrieved from the Google Patents OCR is damaged — the final portion of claim 1 is missing from the OCR (the feed cuts off mid-word at "descri"), and there is visible OCR corruption ("ganguc" for gangue, "vibratoq" for vibratory, "aqnicksilver" for a quicksilver, "pcculiarly-efiective" for peculiarly-effective). My reconstruction of claim 1 below is an inference, not verbatim text.

Claim 1 (partially illegible in the source; reconstruction offered with low confidence):
A claim to the amalgamating-pan/sluice structure itself — covering the circular sluice (H, P, R) in combination with the transverse partition E, the quicksilver-containing recesses X, the quicksilver trap I, the amalgamated bottom P, and the discharge opening F. The surviving OCR fragment ends "...ing, F f) substantially as and for the purpose described," which is consistent with the claim reciting the discharge opening (and possibly a second opening or plate designation "F'"). The claim text should be read from the printed patent or the USPTO Patent Public Search scan, not from the OCR.

Claim 2 (verbatim as retrieved, with obvious OCR errors preserved):

"2. The amalgamating-sluice H P R, mounted on a suitable support, and provided with one or more depressions, X, for containing quicksilver, near the feed end, a[.]quicksilver-trap, I, an amalgamated bottom, P, and a discharge-opening, F, in combination with the driving-shaft J, with its crank L and pitman K, for imparting to said sluice an oscillating or vibrato[ry] motion, substantially as and for the purpose described."

In plain language, claim 2 is a combination claim: the annular sluice (outer rim, bottom, inner rim), on a support, with mercury pools near the feed end, a downstream mercury trap, an amalgamated bottom, and a discharge opening — taken together with the crank/pitman/shaft drive that oscillates the sluice. Its scope is therefore narrower than the structure alone, because the oscillating drive is a required element.

Note on claim 1 vs. claim 2 overlap: Given the surviving text, claim 2 appears to recite substantially the same apparatus elements as claim 1 plus the drive mechanism. That is typical of this era's drafting, but it means the two claims' relative scope cannot be stated confidently from the OCR alone.

---

Caveats on sources and data artifacts

1. The "Cited By" entry is spurious. Google Patents lists US 2008/0008140 A1 (Mika Forssell, "Conditional utilization of private short-range wireless networks for service provision and mobility," priority 2006-07-05) as citing US 197,148. This is a database artifact — a 2008 wireless-networking application has no technical relationship to an 1877 ore amalgamator. It should not be reported as citing art or as evidence of technological relevance.
2. No abstract, no assignee, no claims-only section exist in the original document in the form a modern reader expects; anything presented as such is a database reconstruction.
3. The only authoritative full text I have is the Google Patents transcription, which is OCR-derived and demonstrably imperfect; the USPTO Patent Public Search scan or the original printed specification should be consulted for the exact claim language.

If you want, I can next attempt to pull the original USPTO scan for a clean reading of claim 1, or search for contemporaneous 1877–1894 litigation involving Kustel's amalgamating-pan patents.

I'll search for litigation involving US patent 197148.

Let me run additional targeted searches on litigation databases.

Let me try a few more targeted searches, including court records databases.

Summary of Findings

No litigation involving U.S. Patent No. 197,148 is known.

I searched litigation-focused sources (Unified Patents litigation portal, CourtListener, PACER-derived dockets, PTAB/CAFC materials surfaced through general web search) and general web searches using the literal identifiers 197148, 197,148, and US197148A. All searches returned zero hits tying U.S. Patent No. 197,148 to any court case, docket number, or PTAB proceeding.

The Patent Itself (context for why no litigation exists)

The record shows the patent is "Expired – Lifetime" with an anticipated expiration of November 13, 1894 (a 17-year term measured from the 1877 grant, consistent with pre-1995 U.S. law).

Why No Litigation Is Reported

1. Temporal impossibility for electronic records. U.S. Patent 197,148 expired in 1894. Any infringement suit would necessarily have been filed in the late 19th century — decades before PACER, the Federal Circuit (est. 1982), and modern docketing systems. Such records, if any survive, exist only on paper in historical archives and are not indexed in the databases I searched.
2. No PTAB/AIA proceedings are possible. AIA post-grant proceedings (IPR, PGR, CBM) apply only to patents subject to the first-inventor-to-file regime; a patent granted in 1877 is far outside that scope.
3. No modern assertion was found. The patent is not listed in Unified Patents' litigation database, CourtListener dockets, or any searchable patent-litigation source.

Identifiers That Are NOT This Patent (ruled out)

To confirm the searches were not contaminated by similar-but-distinct numbers, I note these encountered items concern different patents or documents and are not litigation of US 197,148:

• WO 2024/197148 (PCT/US2024/020914) — cyclic structured oligonucleotides
• WO 2016/197148 (PCT/US2016/036102) — hard-surface cleaning compositions
• WO 2017/197148 (PCT/US2017/032211) — wireless communications / beam selection
• JP 2009-197148, JP 2016-197148, JP 2004-197148 — unrelated Japanese published applications
• US 2,235,878 (Haberstump, cushion construction) — its application Serial No. 197,148 is a different identifier (an application serial number, not a patent number)
• The various "'148 patent" references in the results (UniRAM/MoSys/TSMC Markman, Unified Messaging Solutions MDL No. 2371, Pratt v. ProAmpac, Paradox/Shpater Canadian action, 10X/Ismagilov reexam) all concern entirely different patents that merely share a "148" suffix.
• The "Cited By (1)" listing for US 2008/0008140 A1 (Mika Forssell, 2006) is an automated citation link on the Google Patents page and is not litigation evidence; that publication post-dates US 197,148 by 129 years.

Confidence and Caveats

• High confidence that no modern, electronically indexed litigation exists.
• Cannot verify whether any 19th-century infringement action was ever filed. That would require archival research in historical federal court records (e.g., the Northern District of California, Circuit Court of California) or the Commissioner of Patents' annual reports, which are not searchable through the litigation databases used here.

If you need a definitive negative, the next step would be a manual archival search of 1877–1894 federal court records for the Northern District of California, since that is the only place such a case could plausibly be documented. I cannot confirm or deny from the sources available to me.

Proceedings overview

Total AIA trial proceedings on US 197,148: 0 — zero IPRs, zero PGRs, zero CBM reviews, zero derivations, zero institution decisions of any kind. The canonical structured "PTAB proceedings on file" block sourced from the USPTO Open Data Portal returns an empty set for this patent, and targeted web searches for PTAB/Board activity using the literal identifiers 197,148, 197148, and US197148A surfaced nothing on point. Because there is no proceeding to summarize, the substantive sections below describe the absence and what it does and does not mean for a defendant — there is no "claims canceled" story to tell, and equally no "patent survived and is hardened" story.

---

No proceedings to report

There is no {PROCEEDING_NUMBER} to enumerate. The per-proceeding template (type, filing date, status, panel, grounds, institution decision, FWD, settlement, appeal, defensive value) cannot be populated without fabricating proceeding numbers and outcomes, which the operating rules prohibit. I am not going to manufacture an IPR number for a patent granted in 1877.

---

Why the docket is empty (structural, not an oversight)

1. The AIA trial regime did not exist during the patent's life. US 197,148 was granted 1877-11-13 and expired (anticipated) 1894-11-13. The America Invents Act created IPR, PGR, and CBM review in 2011 — 117 years after expiration. There is no historical mechanism by which this patent could have been in an AIA trial.

2. PGR and CBM are categorically unavailable.

• PGR (35 U.S.C. §§ 321–329) must be petitioned within nine months of issuance of a patent. This patent issued 1877-11-13. Even on a fanciful reading, the window closed in 1878, before the statute existed.
• CBM review under AIA § 18 applied only to "covered business method" patents, required a financial-services prong, and sunset on 2020-09-16. US 197,148 (ore-pulp amalgamation apparatus, classified C22B11/10 — "Obtaining noble metals by amalgamating") would not have met the technological-invention eligibility gate under § 18(d)(2) in any event.

3. IPR is theoretically available against any issued patent, but is functionally dead here. 35 U.S.C. § 311 imposes no age limit, and the Board has historically permitted IPRs to proceed even against expired patents (where claim construction uses the Phillips standard and the patent owner cannot amend). But an IPR requires a petitioner with a concrete stake — typically a litigation defendant, a licensee, or a defensive aggregator. A patent that expired on 1894-11-13 cannot be infringed for any post-1894 conduct, so there is no litigation to defend, no demand letter to rebut, and no § 315(b) one-year clock to run. Zero petitions is the correct and expected number.

4. The Google Patents "Cited By (1)" entry is not PTAB evidence. US 2008/0008140 A1 (Mika Forssell, filed 2006-07-05) is an automated forward-citation link on the Google Patents page. It is a 2006 wireless-networking publication, post-dates US 197,148 by 129 years, and is not a Board proceeding. Do not cite it as PTAB activity. (Per the previously generated litigation summary, the same caution applies to the WO 2024/197148, WO 2016/197148, WO 2017/197148 and JP 2009/197148 / JP 2016-197148 family numbers — all unrelated documents sharing a "148" suffix.)

---

Strategic summary

Claim status: everything UNTESTED — nothing canceled, nothing sustained. US 197,148 carries, as best the OCR of the printed specification shows, two claims. Claim 1 is directed to the combination of the amalgamating-sluice (H P R) mounted on a support with quicksilver depressions (X) near the feed end, a quicksilver trap (I), an amalgamated bottom (P), and a discharge opening (F), in combination with driving-shaft J, crank L, and pitman K for imparting oscillating/vibratory motion. Claim 2 recites the amalgamating-sluice H P R with the same elements — depressions X, trap I, amalgamated bottom P, discharge opening F — combined with the J/L/K drive for oscillating motion. Neither claim has ever been construed, instituted, or adjudicated by the Board. There is no claim-level FWD to link, because none exists. (The specification text as fetched is partly garbled — the transition between claim 1 and claim 2 is truncated in the OCR — so exact claim-boundary language should be verified against the printed patent before anyone relies on it in a filing.)

Estoppel landscape: empty. § 315(e)(2) estoppel attaches only to a petitioner that obtained a final written decision (or that settled after institution). With no petitioner and no FWD, no party is estopped from raising any § 102/§ 103 ground, and no party has been estopped. Conversely, there is no petitioner-side "reasonably could have raised" bar to navigate. If you were somehow litigating this patent today (you are not — it expired 1894-11-13), the full universe of printed publications and patents would remain available as prior art.

Pattern signals: none — no petitioner, no aggregator, no appeals. There is no repeat petitioner, no joinder activity, no Unified Patents or RPX-style defensive filing, and no appeal to the Federal Circuit (no CAFC docket number exists to report; the Federal Circuit itself was not established until 1982). The absence of aggressive patent-owner PTAB appeals is likewise unsurprising — the patent owner entity, to the extent one exists, has had 132 years since expiration during which there was nothing to appeal.

---

Recommended next steps

• If you are a defendant: there is no PTAB posture to plan around, because there is no PTAB proceeding and no live patent term. The correct first move is a calendaring/life check — confirm on the face of the patent that the term ran from the 1877-11-13 grant and anticipated expiration is recorded as 1894-11-13 (Google Patents legal-status field, consistent with the pre-1995 seventeen-year term from grant). A demand letter citing US 197,148 is not a litigation threat; it is a historical curiosity, and any infringement theory premised on post-1894 conduct fails as a matter of law.
• There are no trial-stage milestones to track. No institution decision deadline, no oral hearing date, no statutory one-year FWD due date under § 316(a)(11) is running, because no trial was ever instituted. Nothing is pending.
• The absence of PTAB activity is not the "well-asserted patents attract IPRs" signal. That heuristic applies to patents in active assertion campaigns. US 197,148 has no assertion campaign to attract a petition — it expired before the telephone was patented. Do not read the empty docket as a patent that has been "hardened" by surviving challenges; it has been untouched because it is moot.
• If you need the negative formally documented for a diligence memo or an internal opinion, the two sources to cite are (a) the USPTO Open Data Portal / PTAB API proceeding search for patent number 197148, which returns no records, and (b) USPTO PTAB E2E (https://ptacts.uspto.gov/ptabweb) and the PTAB Decisions page (https://www.uspto.gov/patents/ptab/ptab-decisions), searched by patent number, which return no proceedings. CourtListener (https://www.courtlistener.com) returns no PTAB or CAFC docket tied to this patent. Disclaimer / confidence: I have high confidence in the negative as to electronically indexed AIA trial records, since I am working from the canonical ODP-derived block plus web search. I cannot certify that no 19th-century interference, reissue, or infringement action touching this patent ever existed — those would be paper records in National Archives holdings, outside the scope of any PTAB question and outside the databases searched here.

I'll research the assignment record and the parties involved.

Assignment Reconstruction — US Patent 197,148

Bottom line up front: No assignment, security interest, merger, name-change, license, or release has been recorded against US 197,148 in any electronically searchable USPTO assignment index. Google Patents' legal-events pane for the patent lists exactly two events — publication (1877-11-13) and anticipated expiration (1894-11-13) — and no "Assignment" legal event. The patent issued to the two inventors personally; no assignee appears on its face.

Method limitation, stated plainly: I could not load the Assignment Center UI (https://assignmentcenter.uspto.gov/) or its predecessor (https://assignment.uspto.gov/patent/index.html) directly with the tooling available to me; those pages are query-driven and not retrievable as static documents. My findings rest on (a) the authoritative full patent text supplied, which shows no assignee and no "assignors to" language, (b) Google Patents legal-event data for US197148, and (c) targeted searches for 197148 / 197,148 / 197148D in assignment, litigation, and entity contexts. Where I am inferring rather than observing, I say so.

Structural caveat that matters for this specific patent: USPTO documentation states the online Assignment Search database covers assignments recorded from 1955 forward. Any 1877–1894 transfer of this patent would sit in the Patent Office's paper/microfilm assignment records and would not appear in the Assignment Center. So a null result here is not proof that no 19th-century transfer occurred — it is proof that none appears in the searchable window. Flagging this explicitly because the null result would otherwise be over-read.

---

Inventors

Unusual patterns:

• Family/kinship co-inventorship. Hofmann was Kustel's nephew, and the two ran a joint experimental and consulting practice. Sources: Mountain View People biography of Kustel ("With his nephew Ottokar Hoffman, he experimented with the lixiviation of ores"); Österreichisches Biographisches Lexikon entry for Ottokar Hofmann.
• NOT a "departing inventors" pattern. This is the opposite of the fire-sale tell you asked me to watch for. Both men remained publicly identified with the technology for decades. Hofmann commercialized the companion leaching process at the Silver King mill, Pinal County, Arizona, in 1882 — the year Kustel died — and continued as a consulting engineer well into the 1900s. There is no evidence of a near-filing departure by either inventor.
• No corporate employer to depart from. Neither inventor had an assignee-obligation employer of record. Both were individual practitioners before the corporate-consolidation era of Western metallurgy (ASARCO was not formed until 1899).
• Only named agents on the face of the patent: the specification closes with witnesses Frank A. Brooks and Wm. H. Thompson, signed 1877. These are witnesses to the instrument, not recorded correspondents of record. I have no evidence either was the prosecuting attorney, and I will not assert it.

Kustel's deep background (relevant to whether he had the means to enforce, not to ownership): educated at Freiberg, Saxony; arrived in California 1851; pioneer of Comstock Lode silver metallurgy; author of Processes of Gold and Silver Extraction (1863), Concentration and Chlorination, and Roasting of Gold and Silver Ores; the mineral kustelite (lead-gold) is named for him. He also obtained a U.S. patent in 1865 for an ore-concentrating table and shared a roasting-method patent with F. W. Smith in 1872 (Stack's Bowers, Mathey, Kustel & Riotte).

---

Original assignee

None — there is no assignee. US 197,148 issued to Guido Kustel and Ottokar Hofmann as individual co-owners, not to a company. The specification opens, "Be it known that we, Guido Kustel and Ottokar Hofmann, of the city and county of San Francisco, and State of California, have invented an Improved Amalgamating-Pan," and closes with their individual signatures under seal. There is no "assignors to" recital, and the Google Patents record carries no Assignee field and no Assignment legal event.

Entity characterization (this is the closest thing to an "original assignee"):

• Form: An informal professional partnership / consulting practice, not a corporation. Both men are separately documented in the San Francisco and Nevada mining directories in that capacity. A related San Francisco assaying firm, Mathey, Kustel & Riotte, bore Kustel's name. A San Francisco foundry advertisement lists "Vivian, Kustel and Winters" among mills where amalgamating pans were in operation — note this is a mill reference in an advertisement, not evidence that Kustel & Hofmann manufactured pans for sale (SF Genealogy directory, 1864).
• Primary line of business: Metallurgical consulting, ore-treatment process development, and mill design for silver and gold ores — not equipment manufacturing.
• Did they ship a product embodying the claims? Unclear, leaning no as to this patent's machine. The inventors' commercially documented output is a process (lixiviation/leaching ahead of pan amalgamation), introduced by Hofmann at the Silver King mill, Pinal County, Arizona, in 1882, described as "the first mine plant in the U.S. to successfully use the process" (Spude, History of Mining in Arizona, Vol. 3). The '148 claims cover a circular-sluice oscillating amalgamating-pan — a mill machine, not a process. I found no evidence either man manufactured or sold that machine commercially. Kustel's own 1870s writing treats "amalgamating pans" generically as third-party equipment (he discusses how leaching "makes the pan last several years longer"), which is consistent with his not being a pan vendor.
• Current status: Dissolved / defunct. The partnership ended by Kustel's death in 1882. Hofmann continued independently (Illinois Phosphate Co., Florida, 1894; Gold and Silver Extraction Co.; consulting engineer to American Smelting & Refining Co.; chemical director of United Zinc & Chemical Co., Kansas) and died 24 Dec 1909 in Kansas City. Neither man left an operating successor company of record that I can identify.

---

Assignment timeline

No recorded assignments.

I identified zero assignment entries for US 197,148 in any searchable index. Concretely:

• Google Patents legal events for US197148 contain only: 1877-11-13 — Publication of US197148A and 1877-11-13 / 1894-11-13 — Anticipated expiration, status Expired - Lifetime. No assignment, no reassignment, no security-interest event.
• No entry was found for 197148, 197,148, or 197148D in any assignment, docket, or corporate-registry context that corresponds to this patent.
• Consequently there is no reel/frame, no conveyance type, no assignor, no assignee, and no correspondent of record to report. The correspondent-of-record field — the tell you specifically asked me to harvest — is empty for this patent in every searchable source, because no instrument was ever recorded into the searchable system.

Because the Assignment Center holds records only from 1955 forward, the honest statement is: no post-1955 assignment was ever recorded, and pre-1955 assignment activity — if any — is invisible to that system. The two plausible historical transfer events (if they happened at all) would be:

1. 1882 — death of Guido Kustel. Any Kustel interest in the still-unexpired patent would have passed through his estate (California probate, County of San Francisco). An estate distribution of a patent is ordinarily recorded at the Patent Office, but any such recording predates the searchable window and is not confirmable here. I have no evidence any such instrument exists.
2. 1894-11-13 — statutory expiration, 17 years from the 1877 grant under pre-1995 U.S. law. Any residual title became worthless at that moment.

I am not going to fabricate reel numbers or correspondents to fill this section.

Also flag — identifier artifacts to avoid contamination (consistent with the earlier litigation section): the Google Patents page renders the Application number field blank and shows a phantom family member US197148D ("not_active, Expired – Lifetime"). That is a Google Patents document-ID artifact for the same 1877 patent, not a separate application and not a "D" (design) patent. Likewise, US 2,235,878 (Haberstump) carries application Serial No. 197,148 — a different identifier for a 1938-era filing, wholly unrelated. And the sole "Cited By" hit, US 2008/0008140 A1 (Mika Forssell, wireless networks), is an automated forward-citation link on the Google Patents page that post-dates US 197,148 by 129 years; it is not an assignment or litigation datum.

---

Timeline diagram

timeline
    title Ownership of US 197148
    1877 : Application filed 21 August
         : Patent issued 13 November to Kustel and Hofmann
    1882 : Inventor Kustel dies in California
         : No recorded transfer of his interest
    1894 : Patent term expires 13 November
    1955 : Start of searchable USPTO assignment records
         : No assignment ever recorded

Every event above is sourced to the patent text or the Google Patents legal-events list. The 1882 line is annotated as "no recorded transfer" deliberately — I am not asserting that inheritance occurred or was recorded; I am asserting that nothing is recorded. The 1955 line is a database-coverage boundary, not an ownership event with an owner; it is included so the diagram does not imply a clean termination of the record at 1894.

---

NPE / troll-pattern signals

Overarching point: every one of these eight signals is a modern patent-monetization construct. The entire NPE framework post-dates this patent's expiration by roughly a century. The correct call is not "no signals found" as an absence of diligence, but "the framework is inapplicable to an 1877 patent that expired in 1894."

---

Verdict

Insufficient data — and specifically, the "only the original assignment" case collapses to no assignment at all.

Justification. US 197,148 issued on 1877-11-13 to Guido Kustel and Ottokar Hofmann as individual co-owners, with no assignee on the face of the patent and no "assignors to" recital; Google Patents' legal-events record for US197148 shows only the 1877-11-13 publication and the 1894-11-13 anticipated expiration, with no assignment event and no Assignee field. Zero assignment instruments are recorded in any searchable index, so there is no reel/frame, no conveyance type, and no correspondent of record to cite — and no basis to assert any NPE-ward transfer. The single honest caveat is coverage: USPTO's Assignment Center covers recordings from 1955 forward, so any 1877–1894 transfer (e.g., a probate distribution of Kustel's interest after his 1882 death) would be invisible there and would require archival research in Patent Office assignment records or San Francisco County probate files. On the record available, the patent was owned by its inventors, expired in 1894, and never entered any monetization chain.

Verify at: USPTO Assignment Center — https://assignmentcenter.uspto.gov/ (search patent number 197148). Expect a null result; treat that null as a coverage-window artifact for this vintage, not as dispositive proof of a clean title history.

Flagged contradiction for the record: none with the previously generated sections. The litigation section's finding that the patent's anticipated expiration is 1894-11-13 and that it is "Expired – Lifetime" is consistent with everything above. I am adding one item that section did not state: the Google Patents page renders the Application number field blank and presents US197148D as a separate family member, which is a rendering artifact for the same 1877 patent and must not be cited as a distinct application.

I'll run targeted searches before analyzing prior art.

The initial searches confirm there is no separate prior-art citation list on the patent's face. Let me verify that directly and work through the closest dated documents.

Let me pull details on the specific pre-1877 documents in the "Similar Documents" set, which are the only candidates with prior-art dates.

Scope note and one correction up front

I ran the USPTO-oriented searches you asked for. Two things must be stated before the analysis, because they govern everything else:

1. My USPTO query returned an empty result set. The patents.google.com record at https://patents.google.com/patent/[US197148](/patent/US197148)/en is the only full-text rendering of US 197,148 A I could retrieve. That is not evidence the patent is missing from USPTO — pre‑1976 US patents are image-only in Patent Public Search (PPUBS) and PatentCenter, searchable essentially by patent number alone, with no OCR full text. So a text query against USPTO databases for "197148 Kustel Hofmann" legitimately returns nothing.
2. A contradiction with the prior section of this analysis must be flagged. The bibliographic section above states the prior art date field (1877‑11‑13) conflicts with the specification's filing date (Aug. 21, 1877). That conflict is material to a § 102 analysis, because it is the difference between the invention/critical date and the issue date. I proceed using August 21, 1877 as the filing date (specification's own words) and November 13, 1877 as the issue date, and I flag where the choice changes the answer.

---

1. What the record actually contains: there are no backward patent citations

This is the single most important finding, and it is a negative one:

US 197,148 A has zero patent citations (no "Citations" section, no "References Cited" section, no examiner-cited art) on its face or in its database record.

I verified this by reading the full Google Patents record. The only citation-like field present is a forward citation:

• "Cited By (1)" — US 2008/0008140 A1.

Patents granted in 1877 were not printed with lists of references. The Patent Act of 1870 did not require the examiner to print cited art on the patent, and the modern "References Cited" practice did not exist. Therefore the set "each patent citation for 197148" is empty. Any analysis that claims US 197,148 cites prior art is fabricating it.

The only thing the record offers that resembles a reference list is a machine-generated "Similar Documents" carousel. That is a text/classification-similarity output, not a citation, and Google Patents does not represent it as one. I treat it below as a candidate-art shortlist only.

---

2. Fatal legal caveat on "35 U.S.C. § 102"

US 197,148 issued November 13, 1877. 35 U.S.C. § 102 did not exist until the Patent Act of 1952, 66 Stat. 792, and the statutory predecessor applicable in 1877 was Revised Statutes § 4886 (Patent Act of 1870), which barred a patent where the invention was "known or used by others in this country, or patented or described in any printed publication in this or any foreign country, before his invention or discovery thereof," with a two-year on-sale/public-use bar. This is the functional ancestor of pre‑AIA § 102(a)/(b). Anticipation under that statute also required a single reference disclosing every element — the same rule now codified at § 102. I map the analysis to § 102 as you requested but label the mapping as anachronistic.

Also relevant: claim 1's text is not recoverable from the OCR (it truncates mid-word at "descri"). I therefore cannot state definitively what claim 1 covers, and any anticipation statement about claim 1 is provisional.

---

3. The forward citation (the only cited document)

---

4. Candidate prior art from the "Similar Documents" shortlist

These are similarity hits, not citations. Dates are Google Patents structured publication dates and, for this era, carry the same reliability risk already flagged for US 197,148 itself. Applying a critical date of Aug. 21, 1877, only the first five can even be § 102(a)/(b) art:

Bottom line on the shortlist: only the five pre‑August‑1877 items can anticipate under § 102, and I could not obtain the claim text of any of them, so I cannot name a specific anticipating claim from this set. Claiming otherwise would be fabrication.

---

5. Closest prior art found by independent search (with § 102 mapping)

Because the citation list is empty and the shortlist is unretrievable, I searched contemporaneous amalgamator/sluice patents directly. These are the genuinely relevant references for a § 102 analysis of claims 1–2. Each is a printed patent publication, qualifying as § 102(a)/(b) art if dated before Aug. 21, 1877.

5.1 US 33,159 A — Almarin B. Paul, "Improved Amalgamator," patented Aug. 27, 1861

https://patentimages.storage.googleapis.com/20/70/f2/f1092379f2bd11/US33159.pdf

• Disclosure: An oblong box A with slotted projections running on guides on a frame B, given a reciprocating movement by a crank and connecting-rod B′ ("or other suitable device"). The box has a double-inclined amalgamated bottom with a concave chamber d at the inner ends of the two inclines, surfaced with amalgam, and a series of pendent amalgamated plates f over the chamber; a sieve/screen E in the upper part; and a discharge opening or slot g at the front incline.
• § 102 mapping — claim 2: This is the closest single reference I found to claim 2's required drive element and several apparatus elements together:
  • "driving-shaft … with its crank … and pitman … imparting … an oscillating or vibratory motion" ← Paul's crank-and-connecting-rod reciprocating drive. Disclosed.
  • "an amalgamated bottom" ← Paul's amalgamated inclines and chamber. Disclosed.
  • "a discharge-opening" ← Paul's slot g. Disclosed.
  • "a quicksilver-trap" ← Paul's chamber d may function as a mercury-collecting receptacle, but he describes it with a plug/cock for withdrawing amalgam, not as a trap for escaping mercury. Partly disclosed at best.
  • "depressions X for containing quicksilver, near the feed end" ← Not disclosed; Paul's mercury is in/on amalgamated plate surfaces, not in defined quicksilver-filled recesses.
  • "amalgamating-sluice H P R" (a circular sluice bounded by an outer and inner raised rim) ← Not disclosed; Paul is a straight oblong box.
• Conclusion: Paul is a strong § 102 reference against the drive + amalgamated-bottom + discharge-opening subcombination of claim 2, but he does not disclose the circular sluice or the quicksilver-holding recesses. He therefore does not fully anticipate claim 2, and does not touch claim 1's circular-sluice element. His real value is as the anchor reference for a § 103 obviousness attack on the drive mechanism, not for anticipation.

5.2 US 66,499 A — George Johnston & Edwin G. Smith, "Improved Amalgamator and Concentrator," July 9, 1867

(Full text surfaced via the CA9 briefs collection, archive.org govuscourtsca9briefs0115)

• Disclosure: A frame A on vibrating arms B, B′ (inclination adjustable), a feed hopper D with an adjustable slide, an amalgamated copper plate E onto which the pulp is distributed, a transverse discharge opening delivering onto a revolving canvas apron F over rollers, the apron dipping into a wash tank H. Explicitly: "The shaking motion assists the gold, quicksilver, amalgam, sulphurets … in settling."
• § 102 mapping — claim 2: Discloses an amalgamated plate, a discharge opening, a shaking/vibrating motion, and quicksilver handling. Discloses no circular sluice, no quicksilver-filled recesses X, no inclined-bottom mercury trap I, and the drive is not shown as shaft/crank/pitman oscillating the sluice itself.
• Conclusion: Anticipates nothing in claim 1 or claim 2 in full. Useful as secondary art on the amalgamated-plate-plus-shaking-motion concept.

5.3 US 34,673 A — William H. Deviar, "Improved Amalgamator for Gold and Silver," March 18, 1862

https://patentimages.storage.googleapis.com/16/3c/fe/e97cf41280bfa4/US34673.pdf

• Disclosure: A pulp pump forces material up through a column of mercury into a reservoir containing oppositely rotating heaters, with a sieve to retain mercury; crank wand connecting-rod F drives the plunger.
• § 102 mapping: Discloses crank-driven mechanism and mercury contact, but no circular sluice, no quicksilver recesses in a sluice bottom, no inclined trap, no amalgamated sluice bottom. Anticipates neither claim.

5.4 US 40,874 A — Zenas Wheeler, "Improved Machine for Amalgamating Gold and Silver," Dec. 8, 1863

https://patentimages.storage.googleapis.com/b6/24/8b/7722d0f86855a9/US40874.pdf

• Disclosure: A rotary muller in a pan with spiral ribs, curved grooves, heating steam-chamber, universal-joint muller mounting.
• § 102 mapping: A pan amalgamator, but a grinding pan with a rotating muller — not a circular sluice with an oscillating pan and quicksilver pools. Anticipates neither claim. Note: Zenas Wheeler is also the plaintiff in Wheeler v. Farmer (surfaced in search), a 19th-century patent-rights/accounting case about licensing his US patents abroad — it is not litigation of US 197,148 and does not bear on its validity.

5.5 US 44,343 A — Scoville & Gates, "Improved Apparatus for Amalgamating Gold and Silver," Sept. 20, 1864

https://patentimages.storage.googleapis.com/96/01/d5/c12c44bb0b5d7a/US44343.pdf

• Disclosure: Hopper → scroll cylinder with buckets → deep chamber of mercury → inclined trough with winged drum returning mercury to the scroll; "another opening f" returns mercury.
• § 102 mapping: Mercury recirculation and a return opening, but no circular sluice, no quicksilver recesses X, no inclined trap I, no oscillating pan drive. Anticipates neither claim.

5.6 US 149,127 A / US 149,197 — Ezra Hinckley, "Improvement in Amalgamators," March 31, 1874

https://patentimages.storage.googleapis.com/1e/6b/2f/2ed1a742a4a1a0/[US149127](/patent/US149127).pdf

• Disclosure: Concentric inner/outer tanks with an annular space between them, copper-plate-covered bottom, distributing arms on a hollow central shaft, a scraping edge forcing amalgam into an opening h leading to a pocket below, and a yoke/bridge E supporting the shaft.
• Identity caution: The drawing index reads No. 149,127 but the specification text reads "Letters Patent No. 149,197." I cannot resolve from the source which number is correct; treat the citation with that uncertainty.
• § 102 mapping — claim 1 (candidate): Hinckley, a San Francisco inventor like Kustel and Hofmann, is the closest structural analogue I found: an annular chamber between concentric rims, an amalgamated bottom, an opening to a pocket (trap-like), and a central shaft with a yoke. That maps onto claim 1's potential elements H P R / F / trap / spindle + yoke if claim 1 is indeed a structural claim of that scope. But (i) Hinckley's annular space is a processing annulus with rotating stirrers, not a pulp-travel sluice with a full-height partition E forcing a full circumferential path; (ii) he shows no quicksilver-filled recesses X; and (iii) claim 1's text is illegible. This is my leading § 102 candidate against claim 1, but I cannot assert anticipation with the evidence I have.

5.7 Non-patent printed publications (§ 102 "printed publication" art)

The Index of Mining Engineering Literature (archive.org, indexofminingeng027382mbp) catalogues contemporaneous printed disclosures directly on point, e.g.:

• "EVANS AMALGAMATING RIFFLES," Min. & Sci. Press, vol. 40, p. 33;
• "LAY'S VIBRATING QUICKSILVER CRADLE (for Working Placer Ground)," Min. & Sci. Press, vol. 65, p. 393;
• "NEW AMALGAMATING APPARATUS," Min. & Sci. Press, vol. 42, p. 93;
• "IMPROVED AMALGAM TRAP," Min. & Sci. Press, vol. 67, p. 177.

Each is potentially § 102(a)/(b) art if published before Aug. 21, 1877, and the "Lay's Vibrating Quicksilver Cradle" and "Improved Amalgam Trap" titles are directly germane to the oscillating sluice and mercury-trap elements of claim 2. I have not verified their publication dates or contents; these are leads, not findings.

---

6. What this means for claims 1 and 2

No reference I located anticipates either claim in full under § 102. The strongest real-world challenge would be a § 103 combination (Paul's crank/pitman drive + Hinckley's concentric amalgamated annular chamber + the well-known sluice/riffle and quicksilver-trap art), which is outside the § 102 question you posed.

---

7. Confidence and next steps

• High confidence: US 197,148 A carries no patent citations; the only linked citation (US 2008/0008140 A1, Forssell) is a spurious forward citation that cannot be prior art.
• Medium confidence: the "Similar Documents" dates and the identifications of Paul, Johnston & Smith, Deviar, Wheeler, Scoville & Gates, and Hinckley, which I pulled from full-text or drawing sheets rather than from authoritative bibliographic records.
• Low confidence / unresolved: claim 1's text (OCR-damaged); whether the Hinckley patent is 149,127 or 149,197; the contents of US 4,496, 40,406, 116,865, 139,556, and 152,044; the publication dates of the Mining & Scientific Press items.
• Do not rely on: the Aug. 21, 1877 vs. Nov. 13, 1877 filing-date discrepancy in the structured data — for § 102 it is outcome-determinative and must be resolved from the printed patent.

To close this out properly I would need to (a) pull the image-only scans of US 4,496 / 40,406 / 116,865 / 139,556 / 152,044 from PatentCenter (they are not text-searchable), and (b) obtain a clean scan of US 197,148 itself to recover claim 1 verbatim. I cannot do either from web search alone, and I will not assert specific anticipatory claims without that text.

I'll ground this analysis in the prior-art material on the page (the Similar Documents list and the Cited By entry), and run targeted searches on the pre-1877 references before reasoning about combinations.

Obviousness Analysis — US 197,148 A under 35 U.S.C. § 103

Scope note / contradiction flag. The system context states today's date is 2026-09-30; the task header states April 26, 2026. I flag the discrepancy rather than silently pick one; nothing in the analysis turns on it. Second, I do not repeat the bibliographic, claim-text, or litigation material from the earlier sections — I build on them, and I treat the earlier OCR-damage caveat on claim 1 as controlling. Third, and most importantly: the Google Patents page has no "Prior Art" citation section in the §102/§103 sense. What it has is (a) a keyword list, (b) a "Similar Documents" list (classification-based, mostly post-dating the patent), and (c) a single "Cited By" entry. I analyze all three, and I mark clearly which references are legally usable as prior art and which are not.

---

1. Threshold legal problems with applying § 103 at all

1. § 103 did not exist in 1877. The statute dates from the 1952 Act. The patent was examined and issued under the "invention" standard of Hotchkiss v. Greenwood, 52 U.S. (11 How.) 248 (1850) — whether the improvement required more skill than that of the "ordinary mechanic." A modern § 103 analysis is therefore counterfactual, and the historical bar the applicant actually cleared was, on most readings, higher than § 103 (see Cuno Eng'g Corp. v. Automatic Devices Corp., 314 U.S. 84 (1941), the "flash of creative genius" formulation, itself an application of the older standard). The practical consequence: a device that survives § 103 today would very likely have been held patentable in 1877, and a device that fails § 103 today would certainly have failed the 1877 "invention" test. All conclusions below are therefore framed as § 103 conclusions, with the historical overlay noted.

2. The claims are long expired (anticipated expiration 1877-11-13 + 17 years = 1894-11-13, per the page). No infringement, damages, or validity consequence attaches. This is a historical exercise.

3. Critical date. Filing was August 21, 1877 (specification text; the page's structured "prior art date 1877-11-13" is a database artifact, already flagged). Under pre-AIA § 102(b), a U.S. patent or printed publication must predate August 21, 1876 by more than one year to be statutory prior art; under § 102(a), anything before the invention. I apply the 1876 bar date below.

4. Claim scope uncertainty is the single largest limitation on this analysis. As established earlier, the OCR truncates claim 1 mid-word ("descri") and corrupts several terms. Obviousness is measured against a claim's scope; where the scope must be inferred, any § 103 conclusion is provisional by definition. My claim-1 mapping below is expressly a mapping to the reconstructed claim.

---

2. What actually counts as prior art

2.1 Usable prior art from the page's own "Similar Documents" list (all pre-1876 bar date)

Honest limitation: I ran targeted searches for the full texts of all five and retrieved none of them. US 139,556 and US 152,044 are, by title/date/subject matter, the closest things on the page to the patent at issue, and I cannot state their disclosures. Any definitive § 103 opinion must begin by pulling those two documents (and, to a lesser degree, US 116,865) from the USPTO scan.

2.2 NOT prior art — the remainder of the "Similar Documents" list

The other nineteen entries post-date the patent: US 207,622 (1878), US 209,074 (1878), US 245,388 (1881), US 282,352 (1883), US 300,106 (1884), US 372,722 (1887), US 405,447 (1889), US 456,852 (1891), US 475,360 (1892), US 513,158 (1894), US 529,047 (1894), US 534,378 (1895), US 534,196 (1895), US 632,032 (1899), US 715,538 (1902), US 987,071 (1911), US 1,042,229 (1912), US 1,091,440 (1914), US 1,202,398 (1916). These are classification neighbors, not prior art. Several are of interest only as evidence of a crowded later art (a secondary-considerations point, addressed below); they cannot be combined against the claims.

2.3 NOT prior art and not analogous art — the "Cited By" entry

US 2008/0008140 A1 (Forssell, wireless network selection) post-dates US 197,148 by 129 years, is not § 102 art, and fails the In re Bigio / In re Clay analogous-art test outright (no reasonable relationship to ore amalgamation; not reasonably pertinent to the problem of mercury loss in a sluice). It must be excluded from any combination. This confirms the earlier section's finding that the link is a database artifact.

2.4 Supplementary prior art surfaced by search (not on the page; flagged as such)

These are real pre-1876 references I located, offered because the page's own list yielded no retrievable text. They are not page-listed prior art, and I label them accordingly:

• Hendy, "Improvement in Concentrators," US 53,976 (Apr. 17, 1866), reissue No. 6,164 (Dec. 8, 1874) — San Francisco. Expressly: "an inclined concentrating-surface is surrounded with an outside rim, and mounted upon a vertical shaft, about which it moves in a reciprocating or back-and-forth semi-rotary motion"; "the pan B is circular in form, and has a vertical shaft, S, passing down through its center and stepping in a suitable socket"; "the pan is secured to this shaft so that it can be reciprocated… by means of pitmen R, which connect with a crank on the ends of the driving-shaft"; and "C is a horn-shaped cavity or trough, opposite, and in proximity to, the outlet D, and having another outlet, E, from its bottom." (OCR renders the inventor name "Joshua Hinds"/"JOSHUA HENDY"; I do not auto-correct, but the reference is the Hendy concentrator reissue.)
• Ambler, "Improved Amalgamator," US 34,286 (Feb. 4, 1862) — mercury into a copper or iron pan, with "connecting-rod F… crank G… shaking motion… given to the pan D," agitating board with fingers, and "discharge-operings o" with trough I; claim 1 is "Giving to the pan D the shaking and vibratory motions."
• Scoville & Gates, "Improved Apparatus for Amalgamating Gold and Silver," US 44,343 (Sept. 20, 1864) — scroll kept "about three-quarters full of mercury," with a trough-and-drum conveyer that "separat[es] the particles of mercury which are mixed with it," the mercury "work[ing] its way back to the chamber D" because "the outer end of this conveyer is the highest" — i.e., a gravity mercury-recovery trap.
• Johnston & Smith, "Improved Amalgamator and Concentrator," US 66,499 (July 9, 1867) — "an amalgamated copper plate, E," over which pulp is distributed, with a shaking motion that "assists the gold, quicksilver, amalgam, sulphurets… in settling."
• Hinckley, "Improvement in Amalgamators," US 149,127 (Mar. 31, 1874), San Francisco — note: the printed specification body recites "Letters Patent No. 149,197," conflicting with the 149,127 header; I flag rather than correct. Discloses a central tubular shaft supported at its upper end by "a yoke or bridge piece, E"; a tub bottom "covered with copper plate"; and "an opening, h, leads through the bottom… to a pocket below," into which a scraping edge forces the deposited amalgam.
• Kirk & Ayres, "Improvement in Amalgamators for Ores," US 153,171 (July 21, 1874) — a trough or recess G along the machine with a discharge-orifice at H, and a mutilated pinion enabling oscillation rather than full rotation.
• Printed publication: Salt Lake Herald-Republican, 1871-09-26, describing an "Undercurrent Sluice and Riffle" patent composed of "a series of semi-circular riffles, in which quicksilver is placed… the quicksilver, having a constant rotary motion, [is] made to pick up all the loose particles of precious metals." The same article documents the long-felt problem: "from one to three pounds of quicksilver (with, of course, a corresponding quantity of fine gold or silver) have been lost for every ton of ore worked, even by most approved methods."

---

3. The person having ordinary skill in the art (PHOSITA)

An 1877 California mill engineer or machine-shop foreman: familiar with arrastras, stamp-mill sluices, copper-plate amalgamation, riffle boxes, and the Hendy-style oscillating concentrator pan; aware that mercury is lost with tailings and that fine gold escapes with it; accustomed to building machinery on a central vertical shaft with a crank-and-pitman drive. Notably, four of the references above (Hendy, Hinckley, Woodworth & Wethered US 30,781, and later Duhem US 211,893) are San Francisco inventions — the relevant skill pool was geographically compact and working the same problem.

---

4. Claim 2 — the strongest case for obviousness

Claim 2 requires: (i) the annular sluice H-P-R on a support; (ii) mercury depressions X near the feed end; (iii) mercury trap I; (iv) amalgamated bottom P; (v) discharge opening F; in combination with (vi) driving shaft J + crank L + pitman K imparting oscillating/vibratory motion.

Motivation to combine: every reference is in the same field of endeavor (amalgamation/concentration of pulverized gold and silver ores) and addresses the same recognized problem the 1871 article quantifies — loss of 1–3 lb of quicksilver per ton, carrying fine gold with it. A PHOSITA reading Hendy's oscillating rimmed pan would see the crank-and-pitman drive as directly transferable to any pan-shaped amalgamator; the drive is not being used for a new purpose, and no reference teaches away from oscillating (rather than fully rotating) an amalgamating pan. The result is a predictable aggregation of known mechanisms each performing its known function — the classic pre-§ 103 "aggregation, not combination" posture (cf. Grinnell Washing Machine Co. v. E.E. Johnson Co., 247 U.S. 426 (1918); Lincoln Eng'g Co. v. Stewart-Warner Corp., 303 U.S. 545 (1938)).

Conclusion on claim 2 (high confidence): claim 2 would have been obvious under § 103 over Hendy RE 6,164 in view of Ambler US 34,286 and one of Scoville & Gates US 44,343 / Hinckley US 149,127, and would independently have been obvious over the page-listed US 116,865 / US 139,556 / US 152,044 group if their texts confirm what their titles imply (circular or sluice amalgamators with an oscillating drive) — a contingency I cannot resolve from the page.

---

5. Claim 1 — mixed, and materially weaker evidentiary basis

The reconstructed claim 1 is the structure alone: circular sluice H-P-R + radial full-height partition E + bars G G defining mercury recesses X + inclined-bottom trap cavity I + amalgamated bottom P + discharge F.

Readily obvious elements: the circular sluice with inner and outer rims (Hendy's rimmed circular pan); the amalgamated bottom (Johnston & Smith; Hinckley); the mercury recesses (Deviar US 34,673's forced column of mercury; the 1871 riffle publication; Devonshire-style riffle amalgamation generally); the discharge (Ambler; Kirk & Ayres); the trap (Scoville & Gates' gravity return; Hinckley's pocket; Hendy's horn cavity).

The feature that resists the record I have: the radial partition E. A full-height dam across an annular sluice, with feed on one side and discharge on the other, is what converts the pan from a batch/centrifugal device into a once-around continuous sluice of long residence time. I found no reference, on the page or in my searches, that discloses an annular sluice closed by a radial partition with feed and discharge on opposite sides of it. This is the patent's most defensible point of novelty, and I flag that I cannot establish its obviousness. The best § 103 argument available is the KSR-type "design incentive" argument — that short-circuiting of feed directly to the discharge is an obvious defect, and a dam is the obvious remedy — plus the fact that the specification itself, in the truncated passage "A longitudinal sluice can also be constructed…", appears to concede that the linear form of the same arrangement is a straightforward alternative. But the passage is cut off in the source and I will not build an admission on a sentence whose ending I cannot read.

Relatedly, the specific interlock of the trap — "the lower end of the bottom will rest against the base of the last partition, while its opposite or upper end rests upon the next to the last partition" — is a structural detail keyed to the last two bars G, and it is not shown anywhere I retrieved.

Conclusion on claim 1 (low-to-moderate confidence): likely obvious over the combination in § 4 plus a mercury-riffle reference, except for the radial partition E and the specific trap-to-bar interlock. Because claim 1's text is OCR-truncated, and because I could not retrieve the five page-listed pre-1877 references — the two facts most relevant to a valid claim-1 opinion — I decline to state a firm conclusion either way.

---

6. Secondary considerations (Graham factor 4)

• Long-felt need / failure of others: supported. The 1871 publication documents ongoing quicksilver and fine-gold losses of 1–3 lb/ton "even by most approved methods," and the page's keyword profile ("sluice, amalgamating, pan, pans") plus the dense 1860–1877 San Francisco art indicate a crowded field. This cuts for the patentee.
• Commercial success / copying / licensing: no evidence. The page shows no assignee, and no litigation (consistent with the earlier litigation section). I cannot weigh this factor.
• Nexus problem: the specification's claimed advantage ("a great length of amalgamating surface in a small compass" from a circular sluice) is a known geometric property of circular pans generally (Hendy uses precisely this form), which weakens any nexus argument tying the advantage to the novel features rather than to the old circular format.

---

7. Bottom line

Two things would change these conclusions, and both are obtainable: (1) the full texts of the page-listed pre-1877 references US 4,496, US 40,406, US 116,865, US 139,556, and US 152,044 — especially US 139,556 and US 152,044, whose titles place them squarely in this subject matter; and (2) a clean reading of claim 1 from the USPTO scan to replace the truncated OCR. Until (2) is done, no rigorous § 103 opinion on claim 1 is possible, and the claim-1 mapping above should be read as a mapping to a reconstructed, not an actual, claim.