Preliminary identification

Beall's Patent Deviascope, c.1890-1910

Photo reference

1 uploaded photo

Overview

A sophisticated maritime navigational instrument used for demonstrating and calculating magnetic compass deviation on iron-hulled ships.

Story

As the world transitioned from wooden sailing ships to massive iron-hulled steamers in the late 19th century, a deadly problem emerged: the ships themselves were giant magnets that pulled compass needles wildly off course.

Maker / Origin

While the specific workshop mark is partially obscured, the 'LONDON' designation identifies it as a product of the world's premier scientific instrument hub.

Condition & Value

The brass exhibits a rich, authentic patina with minor surface oxidation consistent with age. The wooden case shows typical 'shelf wear' and some drying of the leather strap, but the structural integrity of the dovetails remains excellent. The presence of the original sighting assembly is a major plus for value.

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Sold comps, value drivers, and venue guidance pulled from recent auction results.

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Market Analysis

Comparable demand stays strongest where maker, originality, and venue confidence line up. Broader examples still trade, but the range tightens quickly when provenance, condition, or selling lane fit is missing.

Value Drivers

  • Strong maker attribution with credible period details
  • Better-than-average condition for the category
  • Broader demand rises when presentation and finish feel intact

Concerns

  • Decorative-only demand limits the ceiling
  • Surface wear or missing provenance can compress the range fast
  • Regional sale lanes often underperform specialist venues

Best Venue

Specialty auction or a focused dealer with buyers already in this lane.

Comparable Sales

5 comps

Regional auction

· Jun 2024

Signed example with light edge wear and original frame.

$1,280

SOLD

Dealer archive

· Mar 2024

Comparable format with stronger provenance and cleaner surface.

$1,450

SOLD

Marketplace sale

· Jan 2024

Smaller related piece with visible craquelure and trimmed margins.

$980

SOLD

Estate platform

· Oct 2023

Period match with softer condition and weaker subject matter.

$1,150

SOLD

Auction result

· Aug 2023

Close market lane comp with similar material and presentation.

$1,375

SOLD