The reason for the high cost of radium is not far to seek. First, the demand for the pure salts far exceeded the supply--and this is still the case, though relief is now in sight. Secondly, the scarcity of radium was due to the enormous amount of time and labor involved in its production. Although radium was discovered and isolated by Mme. Curie in 1898, 22 years later--at the close of 1920--scarcely 140 grams (or about five ounces) of pure radium salts had been extracted and put on the world market. Of this amount, about 70 grams had been produced in the United States (during the preceding seven years). The market value of the standard salts was at this time about $100,000 a gram (about 1/28 ounce). Eighteen grams were produced in this country in 1920, and the value of the purified salts was quoted in some journals as $2,160,000. At this price, about $100,000 worth of radium could be put into a glass tube about the diameter of a very coarse pencil lead and not more than an inch in length. To produce the gram of radium salts presented to Mme. Curie by the women of America (in May, 1921), 500 tons of carnotite ore--containing two percent or less of uranium oxide--were treated, consuming in the process 1,500 tons of coal, more than a ton of chemicals, and over 30 tons of water. ALL MATTER RADIOACTIVE While certain substances have been designated as “radioactive,” it is not to be understood that these bodies alone emit charged particles, or radiant energy. “All bodies whatever are a constant source of visible or invisible radiations, which, whether of one kind or the other, are always radiations of light” (Le Bon, “The Evolution of Forces,” p. 318, 1908). Compounds of potassium, and also of rubidium, caesium and lanthanum, as shown by Campbell, Wood, McLennan, Kennedy, and other investigators, possess very high radioactive properties. While the atomic weight of potassium is only about 39, and of rubidium about 84, the typical radioactive elements have atomic weights ranging from 200 to 238. Of the 12 to 15 elements essential to life, potassium is the only one possessing distinct if minute radioactivity. “The activity of potassium may readily be demonstrated by means of the goldleaf electroscope. It is shown that Beta rays are emitted” (Burns). But potassium is 1000 times weaker than uranium, and 1,000,000,000 times weaker than radium, in the emission of Beta (negative) rays. Caesium and lanthanum emit Alpha (positive) rays. Professor Dufour, the distinguished French scientist, has shown that even air that has been breathed emits radioactive particles. The presence of radioactive matter in the atmosphere has been shown to account for its electric conductivity. Thomson found (1906) that many specimens of water from deep wells contain a radioactive gas, and Elster and Gertel have found that a similar gas is contained in the soil.