Which thematic progression pattern has been used in this paragraph? The inventor of the diode valve was Fleming. He made use of the fact, first noticed by Edison, that an electric current could be made to flow across the empty space between the hot filament of an electric lamp and another metal electrode placed inside the evacuated bulb. This effect depends upon the thermionic emission of electrons from the heated metal filament. (W. P. Jolly, (1972). Electronics, p. 61)