It was not until the introduction of a new class of explosive by Alfred Nobel in 1867 that reproducible evidence of the internal cavity of the Earth could be demonstrated. A sequence of dynamite charges were placed along an axis and detonated with a signal delivered by a telegraph line. The generated wave propagated through the solid stone of the crust and the reflected wave was detected by a similar sequence of Palmieri seismographs. Later in the same year the first reports from a expedition which had traversed the Chinese portal to the land of Symzonia was made public. Many of the statements within this initial report were met by great academic and public skepticism, bringing the very existence of the Earth's hollow into question. Many notable personages were willing to stake their very reputation on the impossibility of such phenomena.