20 THE ALUMNI JOURNAL 



As a result of this intra-atomic upheaval there follows a violent 

 explosion or disruption of the atoms, whose constituents are carried 

 far beyond their usual powers of mutual attraction and the disintegra- 

 tion is recognized and made conspicuous by aid of a special instrument 

 called a Spinthariscope, which shows the electro-positive particles 

 flying off from the atom at a tremendous velocity, approximately 20,000 

 miles per second. These particles escaping from their parent mass 

 o-ive rise to considerable heat, which according to recent calculations 

 is about 1,000,000 times greater than in the most violent chemical 

 reaction. Radium will heat its own weight of HoO through 100 de- 

 grees C. per hour. Furthermore, if these positive particles are passed 

 into a magnetic field they are deflected to the left. 



About 200,000,000,000 of thse Alpha particles are expelled from one 

 gram of Ra. every second. Still, the atoms in Ra. are so numerous 

 that this emanation can continue for years, without sensible alteration 

 diminution in quantity of Radium. They do not possess very great 

 penetrative power, but are readily intercepted by thin layer of air or 

 cardboard. 



Still looking to the Spinthariscope it is noticed that there are other 

 and different particles flying off from the atom. They are detected in 

 part by their extreme smallness, being only about one one-thousandth 

 (1-1,000) the diameter of an atom of H. Also by their greater ve- 

 locit_v which approximates 170,000 miles per second. Another charac- 

 teristic is that if they are passed into a magnetic field they are deflected 

 to the right. Their powers of penetration are far greater than the 

 Alpha particles readily passing through sheets of lead or iron of a few 

 millimetres thickness. Then lastly, for our consideration is the Gamma 

 ray or X-ray which results from the disturbance of the ether lying 

 between the particles of the atom. It seems probable that the electrons 

 alone are responsible for this ethereal pulsation when we consider the 

 following facts. That the electrons are found to be identical with the 

 tiny particles which emanate from the cathode in a Crook's vacuum 

 tube. They are negatively charged with electricity, and their velocity 

 approximates that of light. There has been a great deal of controversy 

 in regard to the real origin of the X-rays. The cathode ray is simply 

 the manifestation of myriads of minute projectiles being thrown off 



