Noble gas in the United States alone. For large-scale use, helium is extracted by fractional distillation from natural gas, which can contain up to 7% helium. Neon, argon, krypton, and xenon are obtained from air using the methods of liquefaction of gases, to convert elements to a liquid state, and fractional distillation, to separate mixtures into component parts. Helium is typically produced by separating it from natural gas, and radon is isolated from the radioactive decay of radium compounds. The prices of the noble gases are influenced by their natural abundance, with argon being the cheapest and xenon the most expensive. As
Copia: Foundations of the Abundant Style book was immensely popular in England and in Europe, at least 85 editions of the book were printed in Erasmus' own lifetime, and countless more after that. Erasmus made three separate revisions to the original text, adding chapters each time. The original 1512 edition contained 153 chapters, which swelled to 206 in the final version that Erasmus completed before his death. Copia: Foundations of the Abundant Style Copia: Foundations of the Abundant Style () is a rhetoric textbook written by Dutch humanist Desiderius Erasmus, and first published in 1512. It was a best-seller widely used for teaching how to rewrite