Chemical characters of the quaternary natural gas and underground water are shown on the following tables and figures. On account of the invasion of the underground water current into the natural gas deposits caused by ordinary wells for agricultural water supply, there is no payable gas field in the downstream districts of the River Kiso and Ibi. But the writer thinks it is quite neccessary to survey the midstream district of these rivers (Amagun, Nakashima-gun, Haneshima-gun, Aichi Pref: Yasuhachi-gun, Yoro-gun, Umitsu-gun, Gifu Pref: Kuwana-gun, Mie Pref.) where the gas quality is better and the present wells are few.
In the southern district of Mishima City, natural gas occurs in the quaternary sand beds, depths of them ranging from 20 to 60m. Distribution of gas seepapes, chemical properties of the natural gas and the gas-water are shown in the figures and tables.
By the use of an electrodialysis apparatus properties of drilling muds has been determined. In this paper the influences of Ca-ion upon drilling muds are described: -When Ca-ion is much dialysed from the drilling mud, it is in good conditions for drilling, and when less dialysed, the mud is spoiled.