Rollins — Cathode Stream and X-Light. 389 



cannot be greater than the diameter of one of his corpuscles, 

 having a mass 1/1000 of an atom of hydrogen. Estimate the 

 thickness on this basis. As a preliminary it is necessary to 

 know the diameter of a hydrogen atom. This requires a 

 liberal use of the imagination, as proved by the different esti- 

 mates. Kelvin said an atom, or a molecule (he did not attempt 

 to distinguish them) was from 1/100000000 to 1/1000000 of a 

 millimeter in diameter. Meyer considered them smaller 

 than a sphere 1/1000000 of a millimeter in diameter, or as 

 small as 0*2 XlO -7 centimeter. The physical chemists require 

 us to believe that a molecule is not a solid. Its atoms 

 are arranged with ether between them. The diameter of 

 an atom, therefore, is not equal to half the diameter of 

 any molecule with more than one atom, while in complex 

 molecules its proportion is smaller. Atomic diameters are 

 probably not greater than 1/3000000 of a millimeter. The 

 corpuscle theory of the cathode stream gives the mass of a 

 corpuscle as not more than 1/1000 of a hydrogen atom. The 

 diameter of a corpuscle would not exceed 1/30000000 of a 

 millimeter. This then would be the depth of the radiant area 

 on the target from which X-light could arise.- 



Consider the following experiment : An X-light tube had 

 its target placed at an angle of 90° with the axis of the cathode 

 stream. As close as possible to the area struck by the cathode 

 stream was a narrow passage in a block of platinum, with 

 openings raised one millimeter above the surface of the target, 

 the length of the passage parallel therewith. Under these cir- 

 cumstances, if X-light arose only from a radiant area on the 

 target, whose depth was measured by 1/30000000 of a milli- 

 meter, direct rays could but to a small extent have illuminated 

 the passage, for this was on the top of a cliff thirty million 

 times as high as the depth of the radiant area at its base, in 

 deep shadow, except the opening nearest the radiant area. If 

 the usual theory had been true, no bright image should have 

 been formed on the fluorescent screen, by light coming through 

 the passage. The light was so bright Fomms' bands were 

 photographed with a short exposure. The experiment also 

 appeared to show that X-light was not composed of the 

 reflected ether vortices of the cathode stream or of minute 

 material particles. As these are supposed to move in straight 

 lines, they would have had difficulty in going into the passage 

 in the platinum block to brightly illuminate the screen. 

 Again, how could material particles shot from a charged anode 

 escape having a charge and being deflected by a magnet? 

 Suppose they did escape without a charge. When they went 

 through charged aluminum they ought to have received a 

 charge and been deflected by a magnet. They were not 

 deflected. Was not the theory of X-light advanced in my 



