Before revision: While the ability of wires to illuminate when supplied with current was first discovered during the Enlightenment, it took more than a century of continuous and incremental improvement, including numerous designs, patents, and resulting intellectual property disputes, until incandescent light bulbs became commercially available in the 1920s.
After revision: While the ability of wires to illuminate when supplied with current was first discovered during the Enlightenment, it took more than a century of continuous and incremental improvement, including numerous designs, patents, and resulting intellectual property disputes, before incandescent light bulbs became commercially available in the 1920s.