tact with the sides of the containing vessel. For this state of matter the term radiant seems at once appropriate and happy, for matter so attenuated exhibits phenomena apparently entitling it to a separate class and name. The radiant-matter tubes are simply bulbs or cylinders of glass several inches long and perhaps three or four inches in diameter, which contain only the most minute traces of gaseous matter. Metallic terminals for electric connection are sealed into the glass. These are given various shapes and positions, so that the behavior of radiant matter under different conditions may be observed. The manufacture of radiant-matter tubes is a work of dexterous glass-blowing. In the simpler forms a plain cylindrical tube is taken as the basis, and is-sealed at one end. After the electrodes have been put in place, the other end is drawn into a fine tube, which is also sealed as soon as the exhaustion has been accomplished. Some of these tubes have been made experimentally in this country and more in England, but the home of this industry is also to be found in the Thüringer Wald. They deserve special mention in this connection, since no other material than glass would serve for such investigations.
The philosopher was formerly represented as a seated figure in a gown, and surrounded by hour-glass and old folios. To-day he is more active. He is better pictured in a blouse, and standing, surrounded with the apparatus of science. In his search for power he has brought new material to his service, and none of greater value than that which enables him to study distant globes, to investigate the inner history of an infinitesimal world, to find out the chemistry of the stars, and to pry into the properties and constitution of matter. But he stands there not in pride. The figure is one which breathes a deep humility. Each victory over the unknown only makes him the more sensible of the infinite world beyond his present vision. The office of science is corrective and disciplinary. It teaches one of its deepest lessons when it opens the eyes to the recognition of that which is unseen. The evolution of true power is the evolution of a spiritual insight which, in perceiving the known, perceives also the existence of something beyond. The greatest service of glass lies not in the definite knowledge which it brings us, but rather in the stimulating possibilities which this knowledge suggests.
