On 8 April 1911, Kamerlingh Onnes found that at 4.2 K the resistance in a solid mercury wire immersed in liquid helium suddenly vanished. He immediately realized the significance of the discovery (as became clear when his notebook was deciphered a century later). He reported that ""Mercury has passed into a new state, which on account of its extraordinary electrical properties may be called the superconductive state"". He published more articles about the phenomenon, initially referring to it as ""supraconductivity"" and, only later adopting the term "superconductivity".