Antique Large Surveying / Engineering Slide Rule with Original Case

Unusual oversized vintage slide rule featuring numerous specialized mathematical and trigonometric scales, including 360°, sin 2α, cos² α, A/B and other calculation scales.

Appears to be an older celluloid-faced wooden rule with a removable/sliding center section. Measures substantially larger than a typical pocket or 10” engineering slide rule.

Maker and exact model are unknown/unmarked as far as I can determine.

Condition is as shown. Rule has age-related discoloration, spotting, scratches and previous-owner pencil markings. Cursor/indicator is missing. Original fitted case is included but is heavily worn, separating and damaged from age.

An interesting early scientific, engineering or surveying instrument suitable for a slide-rule collection, restoration, display or study.

Sold as pictured. Please review all photos carefully for condition, scales and included components.