"J. J. Thomson, by a rotating-mirror method, succeeded in measuring the velocity of the cathode rays, finding it to be 1.9 x 107 cm./sec.; a value so much smaller than that of the velocity of light that it was scarcely possible to conceive of the rays as vibrations of the aether."
Sir Joseph John Thomson was a British physicist. He received the 1906 Nobel Prize in Physics "in recognition of the great merits of his theoretical and experimental investigations on the conduction of electricity by gases." In 1897, he showed that cathode rays were composed of previously unknown negatively charged particles, which he calculated must have bodies much smaller than atoms and a very l
"As the cathode rays carry a charge of negative electricity, are deflected by an electrostatic force as if they were negatively electrified, and are acted on by a magnetic force in just the way in which this force would act on a negatively electrified body moving along the path of these rays, I can see no escape from the conclusion that they are charges of negative electricity carried by particles of matter."
J. J. Thomson"The discovery by Monsieur and Madame Curie that a sample of radium gives out sufficient energy to melt half its weight of ice per hour has attracted attention to the question of the source from which the radium derives the energy necessary to maintain the radiation; this problem has been before us ever since the original discovery by Becquerel of the radiation from uranium."
J. J. Thomson"The difficulties which would have to be overcome to make several of the preceding experiments conclusive are so great as to be almost insurmountable."
J. J. Thomson"We see from Lenards table that a cathode ray can travel through air at atmospheric pressure a distance of about half a centimetre before the brightness of the phosphorescence falls to about half its original value. Now the mean free path of the molecules of air at this pressure is about 10-5 cm., and if a molecule of air were projected it would lose half its momentum in a space comparable with the mean free path. Even if we suppose that it is not the same molecule that is carried, the effect of the obliquity of the collisions would reduce the momentum to half in a short multiple of that path. Thus, from Lenards experiments on the absorption of the rays outside the tube, it follows on the hypothesis that the cathode rays are charged particles moving with high velocities, that the size of the carriers must be small compared with the dimensions of ordinary atoms or molecules. The assumption of a state of matter more finely subdivided than the atom of an element is a somewhat startling one; but a hypothesis that would involve somewhat similar consequences—viz. that the so-called elements are compounds of some primordial element—has been put forward from time to time by various chemists."
J. J. Thomson"Notes on Recent Researches in Electricity and Magnetism, published in 1883, had won him enough acclaim at the age of twenty-seven that he was named director of the [Cavendish] laboratory the next year."
J. J. Thomson"Thomson and then his young men demolished a recurrent scientific myth—one that had surfaced again in the 1870s: that there was nothing left to be discovered, nothing new under the sun. Part of the immutable wisdom of the day, endorsed and believed long before the greatest of scientists, Isaac Newton, was a kind of billiard ball theory of the atom, which went back to the ancient Greeks. The word itself is from the Greek atomos, meaning "inidivisible."
J. J. Thomson