{"product_id":"antique-artificial-horizon-instrument-in-mahogany-case-with-mercury-bottle-in-fitted-wooden-carrying-box-20261101","title":"Lot 096 - Antique Artificial Horizon Instrument in Mahogany Case with Mercury Bottle in Fitted Wooden Carrying Box","description":"Antique artificial horizon instrument used in celestial navigation. The device consists of a shallow trough with a black glass or obsidian reflector set into a mahogany frame, held in place by four brass leveling thumbscrews and a glass spirit level. A hinged mahogany roof-shaped cover with felt light-seal strips protects the reflector from wind disturbance during use. The instrument allowed a navigator on land to take sextant readings where no natural horizon was available: mercury was poured into the trough to create a perfectly level reflective surface, and the navigator would measure the angle between a celestial body and its reflection in the mercury pool, halving the result to obtain the altitude. The brass hook clasp on the front secures the cover to the base.\u003cbr\u003e\u003cbr\u003eThe lot includes a separate hinged wooden carrying box with brass drop handles and a keyhole escutcheon, containing a two-tone stoneware jug stenciled \"MERCURY\" with a cork stopper. The jug is empty. The carrying box interior is fitted with angled bracing to hold the jug securely during transport.\u003cbr\u003e\u003cbr\u003eBoth cases show wear, scratching, and surface scuffs consistent with age and field use. The mercury jug has a small chip to the glaze on the body.","brand":"Granite Union Auction Company","offers":[{"title":"Default Title","offer_id":54025489023265,"sku":"20261101-LOT096","price":999999.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0073\/9101\/9067\/files\/20261101-246-001.jpg?v=1792784308","url":"https:\/\/graniteunionauction.com\/products\/antique-artificial-horizon-instrument-in-mahogany-case-with-mercury-bottle-in-fitted-wooden-carrying-box-20261101","provider":"Granite Union Auction Company","version":"1.0","type":"link"}