Abstract: A sight-testing ambulance bus for performing ophthalmologic examinations and providing appropriate spectacles expediently in rural areas, in which the instruments being sensitive against mechanical vibration of the chassis of the bus excited by movement in the bus are supported independently from the bus by support rods extended through holes in the bus-floor and standing on the ground under the bus. The support rods are fixed on the bus floor when the bus is moving and shock-absorbers protecting the instruments from vibrations when the bus is driven.

Abstract: A method for electrolytic removal of a galvanic nickel, chromium or gold layer from a metal base of copper or copper alloy, which is carried out in a bath comprising sulphuric acid and phosphorous acid and/or an organic acid in a concentration, in which the potential of the outer layer is negative and that of the metal base is positive relative to the bath. With such conditions the outer layer will be electrolytically removed and the surface of the metal base gets passive. The removal is finished when the current through the bath decreases below a predetermined threshold value.The apparatus for carrying out the method comprises a current sensor for detecting the current, and if the current decreases below the threshold value, the sensor turns on a current breaker for breaking the current through the bath.