ATMOSPHERIC GASES-NAMELY, COMPRESSED AIR; U.S.P. OXYGEN; OXYGEN; WATER PUMPED, OIL PUMPED AND PRE-PURIFIED NITROGEN; ARGON; LIQUID OXYGEN; LIQUID NITROGEN AND LIQUID ARGON; HYDROGEN; HELIUM; CARBON MONOXIDE; CARBON DIOXIDE; CYCLOPROPANE; METHANE; ETHYLENE; PROPANE AND VARIOUS OTHER LABORATORY GAS MIXTURES MADE BY COMBINING THE FOREGOING GASES