Inspired by Geissler tubes and by Daniel McFarlan Moore's invention of a nitrogen-based light (the "Moore tube"), Claude developed neon tube lighting to exploit the neon that was produced as a byproduct of his air liquefaction business. These were all "glow discharge" tubes that generate light when an electric current is passed through the rarefied gas within the tube. Claude's first public demonstration of a large neon light was at the Paris Motor Show ("Salon de l'Automobile et du Cycle"), 3–18 December 1910. Claude's first patent filing for his technologies in France was on 7 March 1910. Claude himself wrote in 1913 that, in addition to a source of neon gas, there were two principal inventions that made neon lighting practicable. First were his methods for purifying the neon (or other inert gases such as argon). Claude developed techniques for purifying the inert gases within a completely sealed glass tube, which distinguished neon tube lighting from the Moore tubes; the latter had a device for replenishing the nitrogen or carbon dioxide gases within the tube. The second invention was ultimately crucial for the development of the Claude lighting business; it was a design for minimizing the degradation (by "sputtering") of the electrodes that transfer electric current from the external power supply to the glowing gases within the sign.