outer diameters for the glass tubing used in neon lighting ranges from 9 to 25 mm; with standard electrical equipment, the tubes can be as long as . The pressure of the gas inside ranges from 3 to 20 Torr (0.4–3 kPa), which corresponds to a partial vacuum in the tubing. Claude had also solved two technical problems that substantially shortened the working life of neon and some other gas discharge tubes, and effectively gave birth to a neon lighting industry. In 1915, a US patent was issued to Claude covering the design of the electrodes for gas-discharge lighting; this patent became the basis for the monopoly held in the US by his company, Claude Neon Lights, for neon signs through the early 1930s. Claude's patents envisioned the use of gases such as argon and mercury vapor to create different colors beyond those produced by neon. For instance, mixing metallic mercury with neon gas creates blue. Green can then be achieved using uranium (yellow) glass. White and gold can also be created by adding argon and helium. In the 1920s, fluorescent glasses and coatings were developed to further expand the range of colors and effects for tubes with argon gas or argon-neon mixtures; generally, the fluorescent coatings are used with an argon/mercury-vapor mixture, which emits ultraviolet light that activates the fluorescent coatings. By the 1930s, the colors from combinations of neon tube lights had become satisfactory for some general interior lighting applications, and achieved some success in Europe, but not in the US. Since the 1950s, the development of phosphors for color televisions has created nearly 100 new colors for neon tube lighting. Around 1917, Daniel McFarlan Moore, then working at the General Electric Company, developed the miniature neon lamp. The glow lamp has a very different design than the much larger neon tubes used for signage; the difference was sufficient that a separate US patent was issued for the lamp in 1919. A Smithsonian Institution website notes, "These small, low power devices use a physical principle called 'coronal discharge'." Moore mounted two electrodes close together in a bulb and added neon or argon gas. The electrodes would glow brightly in red or blue, depending on the gas, and the lamps lasted for years. Since the electrodes could take almost any shape imaginable, a popular application has been fanciful decorative lamps. Glow lamps found practical use as electronic components, and