Argon

{ar;-gon) [apyoc, inactive]. A new element discovered in the atmosphere in 1894 by Lord Rayleigh and Prof. Ramsey. Its symbol is A; the atomic weight has not been definitely determined, but is thought to be 19.7. It is soluble to the extent of 4 volumes in 100 of water, and condenses to a colorle liquid at — 1 28. 6° C. and under a pre ure of t>2> atmospheres, the liquid having a density of 1.5. Argon may be obtained by freeing air which has been deprived of its carbon dioxid and water, from oxygen by means of red-hot copper, and then absorbing the nitrogen by means of metallic magnesium. The residual gas, the pa age of the gases being repeated a number of times, is argon. Chemically, it is the most inert element yet known. Argyll Robertson Pupil. See Signs and Symptoms, Table of, and Pupil. 78