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Discovery of anode rays(protons)

Discovery of anode rays(protons):
The fact that electron is a universal consitutent of all matter suggests the presence of some positively charged particle also within the atom.This must be so since,atom as a whole is electrically neutral. The discovery of positive rays by goldstein(1886)confirmed the existence of such particles.Goldstein repeated the discharge tube experiment employing a perforated cathode.On passing high voltage electric current between the electrodes,rays starting from anode perpendicular to its surface appeared at the back of cathode. These rays were found to possess positive charge.These rays were,therefore,called positive rays or anode rays.
Properties of anode rays:
The properties of the anode rays were studied in the same way as those of cathode rays. A few important properties are as follows:
(1).Anode rays travel in straight lines at right angle to the surface of anode.They originate in the space between the cathode and the anode and move towards cathode.
(2).Like cathode rays,they also consist of material particles and rotate the paddle wheel when placed in their path.
(3).Anode rays are made up of positively charged particles. In an electric or magnetic field,they are always deflected towards the negative field.
(4).Like cathode rays,they also produce heating effect when struck against a metal foil.
(5).The magnitude of charge on positive particles varies from one particle or the other depending
upon the number of electrons lost by an atom.The total charge on each particle is either one unit positive or some whole number multiple of it.
(6).The mass of the positive particles depends upon the nature of gas in the discharge tube.
(7).The ratio charge to mass of anode rays i.e., e/m is not constant but depends upon the 
nature of gas. It was maximum for hydrogen gas and its value was 9.58*10000 coulombs per gram.
Its charge was found to be 1.60*10-19 coulomb which is opposite in sing and equal in magnitude to charge of an electron.
A proton may be defined as sub-atomic particle which carries one unit positive charge and has a mass nearly equal to that of hydrogen atom.
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