An English physicist named Joseph John Thompson took the discharge tube research further. He measured how much heat cathode rays would produce, how much they could be bent, and other procedures, and by doing all that, he was able to estimate the mass of the rays. Through his research, he concluded that cathode rays weren't rays at all, but in fact were very light/small negatively-charged particles.
He ended up calling these 'corpuscles'. They are now generally called as electrons. Thompson imagined that these negatively charged electrons were distributed randomly along a positively charged matrix. He compared it to a plum pudding, where the 'positively matrix' being the cake, and the 'electrons' being the fruits randomly scattered along the inside of the cake. The model is addressed to as the 'plum pudding model'. Despite of an electron's motion being random, the overall distribution is not.