Caelus, Dry Ice, Freon, Olympian heights, Pentothal, acme, aerial heights, air, airy nothing, ammonia, apex, azure, blue sky, bubble, caelum, canopy, canopy of heaven, carbon dioxide, cerulean, chaff, chip, chloroform, cobweb, cocaine, coolant, cope, cork, dizzy heights, down, dust, elevation, eminence, empyrean, ethyl chloride, ethylene, fairy, feather, firmament, flue, fluff, foam, freezing mixture, froth, fuzz, gas, gossamer, heaven, heavens, height, heights, hyaline, ice, ice cubes, illusion, lift, lifts, liquid air, liquid helium, liquid oxygen, menthol, mist, mote, nitrous oxide, ozone, phantom, raise, refrigerant, rise, rising ground, shadow, sky, smoke, spirit, sponge, spume, starry heaven, steep, stratosphere, straw, the blue, the blue serene, thin air, thistledown, uprise, vantage ground, vantage point, vapor, vault, vault of heaven, welkin, zenith
levity, lightness, imponderability, buoyancy, volatility, feather, dust, mote, down, thistle, down, flue, cobweb, gossamer, straw, cork, bubble, balloon, float, buoy, ether, air, leaven, ferment, barm, yeast, lighter-than-air balloon, helium balloon, hydrogen balloon, hot air balloon, convection, thermal draft, thermal, light, subtile, airy, imponderous, imponderable, astatic, weightless, ethereal, sublimated, gossamery, suberose, suberous, uncompressed, volatile, buoyant, floating, portable, light as a feather, light as a thistle, light as air, lighter than air, rise like a balloon, float like a balloon.
rarity, tenuity, absence of solidity, subtility, subtilty, subtlety, sponginess, compressibility, rarefaction, expansion, dilatation, inflation, subtilization, vaporization, evaporation, diffusion, gassification, ether, rare, subtile, thin, fine, tenuous, compressible, flimsy, slight, light, cavernous, spongy, rarefied, unsubstantial, uncompact, incompressed, rarefiable.
gaseity, vaporousness, flatulence, flatulency, volatility, aeration, aerification, elastic fluid, gas, air, vapor, ether, steam, essence, fume, reek, effluvium, flatus, cloud, ammonia, ammoniacal gas, volatile alkali, vacuum, partial vacuum, pneumatics, pneumatostatics, aerostatics, aerodynamics, gasmeter, gasometer, air bladder, swimming bladder, sound, (of a fish), gaseous, aeriform, ethereal, aerial, airy, vaporous, volatile, evaporable, flatulent.
insensibility, physical insensibility, obtuseness, palsy, paralysis, paraesthesia, anaesthesia, sleep, hemiplegia, motor paralysis, vegetable state, coma, anaesthetic agent, opium, ether, chloroform, chloral, nitrous oxide, laughing gas, exhilarating gas, protoxide of nitrogen, refrigeration, insensible, unfeeling, senseless, impercipient, callous, thick- skinned, pachydermatous, hard, hardened, case hardened, proof, obtuse, dull, anaesthetic, comatose, paralytic, palsied, numb, dead.