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**Antique Pre-WWII Jas. P. Marsh & Vilter Mfg. Co. Ammonia Compound Gauge (c. 1920s-1940s)**Up for sale is a premium, authentic piece of early 20th-century American industrial history. This antique compound gauge was custom-manufactured by the prestigious **Jas. P. Marsh Corporation (Chicago)** for **The Vilter Manufacturing Co. (Milwaukee, WIS.)**—a historic giant renowned for engineering massive industrial ice plants, commercial refrigeration units, and brewery chilling systems during the Pre-WWII era.**Historical Diagnostics & Dating:**
* **Era Verification:** The face features the distinct \"Jas. P. Marsh Corporation\" text format which was established after the company\'s late-1920s incorporation.
* **Patent Status:** Stamped \"Patents Applied For,\" dating this piece to the active innovation window of the 1930s before postwar patent finalizations.**Key Features & Physical Condition:**
* **Dual-Scale Dial Face:** Features a crisp black inner pressure/vacuum scale (30 in. Hg VAC to 300 PRESS. PSI) paired with a striking, highly legible outer red scale mapping the corresponding saturation temperature for Ammonia (TEMP F°).
* **Aesthetic Appeal:** Beautiful vintage patina. The pointer needle rests perfectly straight at the zero line. The rugged black-painted metal casing shows localized scuffs and paint chipping that tell the story of its real-world industrial workshop heritage.
* **Capped & Protected Base:** The lower threaded pipe fitting comes with a protective cap installed, keeping the internal inlet port and threads completely free of modern dust and debris. Includes a vintage protective cardboard wrap segment.**Testing & Functionality:**
This item is UNTESTED and is being sold strictly as a historic industrial collectible, machine age artifact, or steampunk display piece. Please review the attached photographs carefully to assess the cosmetic condition. Ships securely packaged in a heavy-duty box with premium bubble wrap to protect the glass front.
