抄録
Natural gas is generally classified in two categories; the flamable gas and the nonflamable gas. Methane, Ethane etc., which belong to the former, are the main constituents of the socalled natural gas, while the helium belongs to the latter.
First, the place of mines and the amounts of production are described for the flamable gas. Secondly, the following items of helium gas are described; the location of mines, the amounts of production, the recovery and the probable reserves and thirdly, the recent world trend in the field of natural gas is discussed.
