The Thomas Radioactive Cone (ca. 1935-1955)

Click here for a detailed history about R.W. Thomas, the Revigator and the Thomas Cone

The Thomas Radioactive Cone (ca. 1935-1955)

The Thomas Cone belongs to a category of devices known as emanators. It was placed in water, usually 1-2 gallons, to infuse the water with radon, a radioactive gas.

The most common cone, 4.5" tall, incorporated approximately 70 grams of carnotite ore as the radon source. The ORAU collection also includes a smaller cone, 2.25" tall. I have heard that larger versions were sold to farmers for use in animal water troughs, but have never seen one. Based on the size of a mold provided by the estate of Earl Pribble, the height of these might have been 5.5."

Named after R.W. Thomas, inventor of the Revigator, the Thomas Cone was first produced in 1935 (or so) in Los Angeles, California. This date is based on the fact that the Thomas Cone Trade Mark was registered Oct 22, 1935 (No. 329287). During WWII, R.W. Thomas died, and the company was transferred to Earl T. Pribble in Lubbock, Texas. Pribble, formerly a regional distributor of the cones, continued to produce them into the 1950s and possibly the early 1960s. He died in 1963.

The Thomas Radioactive Cone (ca. 1935-1955)

Read a detailed story about the Thomas Cones, R.W. Thomas and the Revigator.

Donated by the Public Health Service courtesy of Don Thompson and Ed Tupin, Leo Spencer with the State of California, and the estate of Earl T. Pribble.

You might also want to check out the molds and stamps that were used to make the Thomas Cones.

Quoting the manufacturer's literature:

"The Thomas Cone when placed in three or four gallons of any water for a period of twelve hours is fully guaranteed to charge it with RADON, GAS or RADIOACTIVITY the same that is found in the best springs of America and equal to the average spring of the United States."

"HEALTH < WEALTH < and HAPPINESS. Having these, you have all, and the greatest of these is health for without health, wealth is valueless and happiness is impossible.

The RADIO-ACTIVE Cone bears the Thomas Trade mark in the bottom of the cone, which is registered in the U.S. Patent Office. Look for the trade mark. BEWARE OF IMITATIONS!

We maintain a staff of educators, not salesmen. One of them is at your service at any time."

The Thomas cone seems to have been based on the cones produced in the 1920s by the Radium Cone Company which had R.W. Thomas identified as the sole owner.

Size: 4 1/2" high, 3 1/2" diameter at base

Exposure rate: ca. 30 uR/hr above background at 1 foot


  • Manufacturer's brochure. Thomas RADIO ACTIVE CONE. No date but probably mid to late 1930s based on dates of reproduced letters.
  • Ray, James A. Personal communication.
  • Wukasch, M.C., and Gilbert, D. Radiation Cones: Device of Quacks. Texas Health Bulletin. Sept.-Oct. 1964.