Faichney Glass Thermometers – Vintage Mercury Fever Thermometers

For much of the 20th century, Faichney Instrument Corporation was one of America’s most respected makers of precision glass mercury fever thermometers. Based in Watertown, Massachusetts, the company earned a reputation for craftsmanship, accuracy, and durability — producing oral, rectal, and basal thermometers trusted by doctors, hospitals, and families alike.

From their finely etched stems to their distinctive cases, Faichney glass thermometers have become prized by collectors of vintage medical instruments. Today, they are lasting reminders of an era when medical tools were built to last for decades.

History of Faichney Instrument Corporation

Founded in the late 1800s in Watertown, MA, Faichney Instrument Corporation specialized in high-precision thermometry and other scientific instruments. By the early 1900s, the company had established itself as a major supplier of mercury-in-glass clinical thermometers, providing them to hospitals, physicians, and pharmacies across the United States.

Faichney products were valued for their accuracy — often calibrated to within ±0.2°F — and for their meticulous construction. The brand competed directly with other major U.S. makers such as Becton, Dickinson & Co., Taylor Instrument Companies, and Eisele & Co., holding its own in both the professional and consumer markets.

Oral and Rectal Faichney Mercury Thermometers

Like other leading manufacturers of the era, Faichney produced separate thermometers for oral and rectal use:

Oral thermometers – Typically 5–6 inches long, with clear or blue-tinted glass tips.
Rectal thermometers – Shorter, sturdier, and tipped in red glass to avoid dangerous mix-ups.

Both types featured a constriction in the capillary tube above the mercury bulb. This trapped the mercury at the highest reading until the thermometer was “shaken down” — allowing the temperature to be read after removal from the patient. This feature made Faichney fever thermometers convenient for doctors, nurses, and home caregivers alike.

Packaging and Branding Through the Decades

Faichney thermometer packaging evolved over the years, making it possible to date many examples by case style and design:

1930s–1940s – Hinged cardboard or nickel-plated brass cases, often in dark green, burgundy, or navy with gold lettering.
1950s – Cardboard slide boxes with cleaner typography and restrained color palettes.
1960s – Lighter, brighter designs and modern sans-serif fonts. Molded plastic slip cases became common.

The thermometer stems were often marked “Faichney’s” along with “Watertown, Mass.”, making identification straightforward for collectors.

Collecting Vintage Faichney Fever Thermometers

Faichney thermometers remain popular among vintage medical collectors for their quality and clarity. Factors affecting collectibility include:

Condition – Mercury column intact, scale legible, glass free of chips.
Completeness – Original case, instructions, and box increase value.
Type – Basal (fertility) thermometers and early pre-war models are especially desirable.
Packaging style – Helps date the piece and appeals to packaging collectors.

Because these are mercury fever thermometers, they should always be stored safely, away from children and pets, and never discarded in household trash.

A Lasting Legacy

Although Faichney Instrument Corporation is no longer a household name, their thermometers stand as a testament to American medical manufacturing at its finest. For decades, these precision tools were part of everyday healthcare — whether in a doctor’s black bag, a school nurse’s office, or the family medicine cabinet.

Today, vintage Faichney glass thermometers are appreciated not only for their historical significance but also for the craftsmanship that has allowed many to survive in perfect working order decades after they were made.