Abstract: The temperature compensation of an ultrasonic measuring device of the concentration of solutions is achieved by application of a reference solution with a maximum speed of propagation of ultrasonic waves and a reference solution with a minimum speed of propagation of ultrasonic waves, by determining differences of time intervals of the speed of propagation of ultrasonic waves of these reference solutions with respect to the measured solution and by dividing the resulting differences.

Abstract: A pressure riveting unit for blind or one-side riveting provided with a two-arm riveting head, there being a pull stud for hollow rivets on the end of each arm. The head is adapted to be turned through 180.degree., thereby permitting the simultaneous fixing of one hollow rivet blank on one pull stud and the forming of a rivet head on a rivet blank which has been previously fixed on the other pull stud.

Abstract: Apparatus for glazing bases of electric bulbs comprising a number of combined tools on the circumference of a continuously rotating rotor, the combined tools consisting of coaxially arranged upper and lower parts, a mold being formed by the lower part. The apparatus includes means for feeding molten glass and for pressing it by the upper part, means for checking the presence of base sleeves and contacts at the working station, and means for removing excess glass in the course of the pressing operation. The apparatus includes means for ejecting a sleeve from the lower part of any tool which does not contain a contact, and means for preventing the feeding of glass to any tool which does not contain a sleeve.

Abstract: Form pieces, particularly rivet heads are formed by point rolling of an active surface of a forming tool along the formed surface by an arrangement wherein the required motion of the forming tool is composed of two components, both of which are derived from rotating motions around an axis coaxial with the axis of the arrangement.

Abstract: Different surfaces of articles are shaped by means of a shaping tool. The active surface of the shaping tool is rolled reversibly along the shaped surface with a point contact in the axial plane of the shaped surface, such axial plane turning around the axis of the shaped surface, the amplitude of this reversible relative rolling being selected arbitrarily.