Central claims: Crookes, "On Radiant Matter" (1879)

Single document in the project (23 pages, OCR text read in full; no source gap). The text is a lecture of live demonstrations. It has no tabulated data, and it gives no pump, gauge, coil voltage, ray velocity or focus temperature. Where the digest differed from the page images (red-line wavelength 6,895; highest vacuum 1/20,000,000 atm; 10^24 molecules in the bulb), the deep read's page-image values are used. [read]

1. At about one millionth of an atmosphere, residual gas is a "fourth state of matter" (Faraday's "radiant matter"), as far from a gas as a gas is from a liquid.
2. The dark space around the negative pole is the mean free path of the residual gas molecules, so at high vacuum the molecules travel from the pole without collisions and must be treated individually.
3. These molecules leave the negative pole in straight lines normal to its surface, independent of the positive pole, cast sharp shadows, and are deflected by a magnet like projectiles.
4. The molecules are negatively electrified, and their impact produces phosphorescence in glass, diamond, ruby and other minerals. The evidence offered for the charge is one demonstration (Fig. 18), kept in two parts. Observation: when a second negative terminal, "close together" with the first, is switched on, the first ray jumps away from it (d f to d g); no pressure, voltage or terminal spacing is given, and the lower ray's deflection is asserted, not shown. Crookes's interpretation: the two streams repel as similarly electrified bodies, so they are not current carriers (parallel currents would attract).
5. The stream carries strong mechanical force and heat: it turns a paddle wheel and radiometer vanes (also when driven by a red-hot platinum ring), and at its focus melts wax, glass and iridio-platinum. For the hot-ring test Crookes gives only "red-hot" and "a very high point" of exhaustion (no temperature, pressure, ring-to-vane distance or control), and reads it as the hot wire setting radiant matter in motion.
6. The effects are the same for hydrogen, carbonic acid and air (only the onset pressure differs), and even at one millionth of an atmosphere a 13.5 cm bulb still holds about 10^18 molecules.
7. At the very highest vacua the tube stops conducting (the spark "refuses to pass"); a trace of residual vapour restores conduction at once, so some gas is needed for the discharge. Crookes shows the onset in the potash tube (Fig. 5) and quotes William Morgan's 1785 experiment on the non-conducting power of a perfect vacuum (pp.7-8).