Abstract
The Daimyojinzawa flows frozen the water shed of Mounts, Neko and Azuma and run southward to join the Tikuma River at the city of Ueda. It is a short stream only 5 Kilometers in length and its waters contain, a poisonous acid. The acid. contents originate from a sulphery mine located at the source of the river. The writer examined the tem-nperat;i.re of the water, its hydrogen ion concentration, and the its amount of discharge at several stations. (Fig. 1, Tab. 1) Analyses of some ingredients were made at 5 Points by taking water samples (Tab. 2). As a result of these observations, the following conclusions were reached:
(1) The acid cotent of the water is increasing due to prospectingat at the sulphur mine.
(2) Although. it is believed that the acid content increases during low water season and decreases, at high water season, it also increases at some high water periodes such as the snow-melting season.
(3) The acid content will increase further when mining is resumed
