Archives Of The Roentgen Ray PDF Download

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1907 Excerpt: ... they consist originally of metallic particles liberated by the disintegration of the cathode, and charged positively by the loss of electrons under the influence of ultra-violet light. They are expelled from the cathode with a negative charge, but this is soon lost and converted into a positive charge, whereupon the particles are driven back towards the cathode. The varying size of the expelled particles accounts for the magnetic " spectrum " observed by Wien. The circumstance that the particles are derived from the metal, and not from the gas, explains why the material of the canal rays is able to exceed the total gaseous contents of the vacuum tube, and also why the mass of the canal-ray particle may be as much as 650 times that of the hydrogen atom. These particles are large enough to be made visible by the ultra-microscopic method devised by Siedentopf and Szigmondy. That they occur in front of the electrode was already known to Goldstein, and their slow motion there is accounted for by their having to proceed for some distance against the electric force. When proceeding with it, they must show the Doppler effect discovered by Stark. The process by which the cathode disintegrates is still obscure. It is not solely due to the electric field, since disintegration may be produced by simple heating. Phosphorescence.--A. Debierne (Comptes Rendus, March 5, 1906) advances a theory of phosphorescence based upon thermoluminescence and the coloration of phosphorescent bodies by the radiation which excites them. Many phosphorescent bodies are coloured during phosphorescence. This coloration is attributable to the formation of a new body, which persists after phosphorescence has ceased. When, however, the phosphorescent bcdy is heated up to a certain tem...