Thermometers: Antique Scientific Instruments & Advertising Collectibles
Antique thermometers span two distinct collecting categories: scientific instruments dating from the 17th century onward, and advertising thermometers produced from the late 19th through mid-20th centuries. Scientific thermometers by makers like Daniel Gabriel Fahrenheit, Negretti & Zambra, and Tycos represent milestones in measuring technology. Advertising thermometers, produced for brands like Coca-Cola, Dr Pepper, and countless local businesses, combine functional utility with colorful commercial art. Both categories offer rich collecting opportunities.
Identification & Types
- Scientific/Laboratory: Precision mercury instruments in brass, ivory, or ebony cases by makers like Negretti & Zambra, Casella, and Short & Mason
- Weather/Barometer Combinations: Aneroid barometers with attached thermometers, often in carved oak or mahogany cases
- Porcelain/Advertising: Enameled metal or porcelain thermometers bearing brand advertising, produced primarily 1890s-1960s
- Tin Lithograph Advertising: Painted or lithographed tin signs with working thermometers, common from 1920s-1960s
- Figural: Novelty thermometers in decorative holders (cast iron, ceramic, wood)
- Clinical/Medical: Early medical thermometers in cases, by makers like Hicks and Aitken
- Industrial: Large-scale factory and dairy thermometers, often brass-cased
Auction Price Ranges
| Item | Price Range |
|---|---|
| Common tin advertising thermometers | $20 - $100 |
| Porcelain advertising (Coca-Cola, etc.) | $100 - $800 |
| Rare brand advertising thermometers | $200 - $2,000+ |
| Weather station/barometer combinations | $100 - $500 |
| Scientific instruments (19th c., brass) | $100 - $600 |
| Negretti & Zambra signed instruments | $200 - $1,500 |
| Early mercury thermometers (18th c.) | $500 - $5,000 |
| Figural/novelty (cast iron, ceramic) | $50 - $300 |
| Galileo-type spirit thermometers | $200 - $1,000 |
Condition Factors
Mercury columns must be intact and functional; broken or separated mercury columns significantly reduce value. Glass tubes should be free of cracks and cloudiness. For advertising thermometers, the condition of the advertising graphics is paramount; fading, rust, and paint loss diminish value. Porcelain advertising thermometers should be free of chips and cracks. Tin advertising signs should retain original surface with minimal rust. Scientific instruments should retain original calibration scales. Wooden cases on barometer/thermometer combinations should be free of worm damage, veneer lifting, and excessive restoration. Original mounting hardware and backboards add value.
Collecting Tips
Advertising thermometers are collected primarily for their graphic appeal and brand identity. Coca-Cola, Dr Pepper, Hires Root Beer, and tobacco brands are among the most sought-after. Porcelain advertising thermometers command premiums over tin equivalents due to durability and visual quality. Scientific thermometers appeal to instrument collectors and require maker identification for proper valuation. Early examples (pre-1800) are rare and museum-quality. Weather station combinations with barometers, hygrometers, and thermometers in carved cases have strong decorator appeal. Beware of reproduction advertising thermometers, which are abundant; originals show age-appropriate wear and period-correct manufacturing methods. The mercury in antique thermometers requires careful handling due to toxicity concerns.