Early Neon Signs (Oct, 1923)

“VACUUM-TUBE” SIGNS YIELD LIGHT AT SMALL COST
“Vacuum-tube” signs, consisting of continuous glass tubing bent into lettering or numerals, the whole being lighted by either direct or alternating current at common voltages, are new advertising features. As many as three lines of script or number units may be arranged in one sign, which displays a deep-red or orange color when illuminated. The operating cost is negligible, as only from 8 to 10 watts are required for any length or number of units. No noticeable heat is radiated from the tubing, which is thus said to yield a “cold” light.