Helium is a chemical element with symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas, the first in the noble gas group in the periodic table. Its boiling point is the lowest among all the elements.
The atom plays a huge devolopment in the series. It is propably involved in the making on the new weapons deployed on the Western Front in 1904.