United States or Vatican City ? Vote for the TOP Country of the Week !
If, therefore, particles are torn off and projected across the tube to cause phosphorescence, these particles will not be particles of glass, but of yttria; and the spot of phosphorescent light, C, on the opposite side of the bulb will not be the dull blue of lead glass, but the golden yellow of yttria.
You see there is no such indication; the glass phosphoresces with its usual blue glow, and there is no evidence that a single particle of yttria is striking it.
See how well the rubies and yttria phosphorescence shows under molecular bombardment, at an internal pressure of 0.00068 millimeter, or 0.9 M. A shadow of an object inside a bulb can also be projected on to the opposite wall of the bulb by means of an outside pole. Here the internal pressure is 0.00068 millimeter, or 0.9 M.
The probable explanation is that the vagrant molecules I introduce in the next experiment, happening to come within the sphere of influence of the positive pole, rush violently to it, and excite phosphorescence in the yttria, while losing their negative charge. By Prof.
Very many bodies, such as ruby, diamond, emerald, alumina, yttria, samaria, and a large class of earthy oxides and sulphides, phosphoresce in vacuum tubes when placed in the path of the stream of electrified molecules proceeding from the negative pole.
Inside the bulb, completely covering the part that would form the negative pole, A, I have placed a substantial coat of yttria, so as to interpose a layer of this earth between the glass and the inside of the tube. The negative and positive poles are silver disks on the outside of the bulb, A being the negative and B the positive poles.
The pressure here is 0.076 millimeter, or 100 M. The next stage, dealing with more rarefied matter, is that of phosphorescence. Here is an egg-shaped bulb, shown in Fig 19, containing some pure yttria and a few rough rubies. The positive electrode, B, is on the bottom of the tube under the phosphorescent material; the negative, A, is on the upper part of the tube.
The composition of the gaseous residue present does not affect phosphorescence; thus, the earth yttria phosphoresces well in the residual vacua of atmospherical air, of oxygen, nitrogen, carbonic anhydride, hydrogen, iodine, sulphur and mercury. With yttria in a vacuum tube, the point of maximum phosphorescence, as I have already pointed out, lies on the margin of the dark space.
Word Of The Day