Abstract :
The subject of light is worthy of exhaustive study. The goal of illuminating engineers is light without heat, or light by luminescence. The common candle was in its time a very useful invention. As the development of light proceeded, various forms of lighting appeared. The advent of the Geissler tube, which in its simplest form is a sealed glass tube with air exhausted to a low point, opened a new field to the electrical engineer. This was followed by the Crookes tube, similar in principle to the Geissler tube, but having a higher degree of vacuum. This led to the discovery of the X-ray. It was in 1891 that the writer, noting a statement that 99.7 per cent of the energy of coal used in producing light is lost, thus only three-tenths per cent of one per cent being utilized, resolved to bend his energies in the direction of developing a more efficient light. The result of his efforts has been the development of a new form of light which has been brought to a high state of perfection. Those who have visited the large stores and public buildings of any of our larger cities have seen the Moore vacuum tube light in actual operation. As usually installed it consists of a long glass tube strung on the ceiling, and giving off a brilliant but soft light. There are two standard qualities of the Moore light; yellow and white. The yellow used for general illumination, employs nitrogen vapor in the tubes. The white, which produces a light exactly similar to the light of day, employs carbon dioxide as a vapor. The white light is the only light by which color values properly can be judged. Its greatest use is in lighting such places as department stores, dye factories, silk mills, etc., where colors are handled. The efficiency of the yellow Moore light is higher than that of any other form of light; that is, it uses less energy for the same effective illumination than any other form of light. Probably the most ingenious feature of the Moore light is the valve which automatically s- pplies the proper amount of vapor to the tube in order to keep the vacuum within the proper range. A plunger, operated by the change in current value, displaces a varying amount of mercury in a tube leading into the Moore tube proper. The mercury normally covers a carbon plug, thus sealing the tube, but with an increase in current the plunger rises, displacing less mercury and uncovering the carbon plug, through which the mercury percolates, thus lowering the vacuum again to the proper point.
