Abstract: Process for increasing the water discharge of water delivering drilled wells, which can be characterized in that into the filter section of the well weak acids with a dissociation constant being less than K.sub.d =10.sup.-3 are introduced. After a dwelling period of longer duration, expediently 10 to 48 hours, as well as compressing, flushing is performed by means of a scavenging pump. Thereafter the solution of sodium bicarbonate and/or sodium hypochlorite is introduced into the filter section. After a longer dwelling period, expediently one to thirty-six hours, flushing is performed by means of the scavenging pump. As weak acids with a dissociation constant being less than K.sub.d =10.sup.-3 acetic acid, tartaric acid, citric acid, metaboric and/or tetraboric acid is used.

Abstract: A toy with balls which is provided with a playing field. The playing field is formed on at least one rotatable disc (92), where the disc (2) is provided with holes (3), the size of which allows falling of the balls (4) freely therethrough. Furthermore it is provided with an assorting unit (6) connectible with the hole (3) of the disc (2), wherein the disc (2) is arranged in cup-shaped house (1) to be held in the hand having a cover (1a) and a side which are made of transparent material. The assorting unit (6) is firmly fixed. The assorting chamber (16) formed below the disc (2) and has as many guiding recesses (11) as the number of holes (3) of disc (2), and wherein the lower end of the guiding recesses (11) is connectible through outlets (17) of a rotatable null-setting disc (13) with a collecting space (18), which is in communication with a preparatory space ( 21) through channel (22), where a feeding key (23) is built in between the preparatory space (21) and playing space (9) above the disc (2).