The cock and key assembly would have regulated the flow of gas, and up-facing glass shades softened the glare of the manufactured (coal) gas. The wall fixtures or sconces were, at the time, called brackets, in reference to the decorative armature coming from the gas pipe in the wall. As for ceiling fixtures, pendants have one or two arms, a gasolier has three or more. Stylish Victorian gas fixtures were made in neoclassical, Gothic, Grecian, Rococo, and Aesthetic styles, often with decorative castings and spun-brass flourishes.
Though electric light was perfected in 1878, service was often unreliable, and gaslight (by now with the improved Welsbach burner) survived through the First World War. Transition fixtures have a downward-pointing arm for electric light and an upward arm for gas. Shown: the ‘Cape May’ brass fixture with ‘Twin Roses’ floral etched shade. Victorian Lighting Works, (814) 364-9577, vlworks.com