Abstract: The present invention relates to a process for the detection of superimposed sheets, the apparatus making it possible to perform this process and the application thereof to bank notes. The process for detecting superimposed sheets by evaluating their surface mass is characterized in that it comprises the stages of passing the sheets oriented in the direction of their width between a beta particle source and a Geiger-Muller counter, counting the number of particles received by the counter by measuring the frequency F.sub.g of the pulses from the Geiger counter to determine the surface mass and eliminating the notes having a high superimposition level by comparison with a limit value.

Abstract: A non-skid device for vehicle wheels having a pair of cables, one for each side of the wheel, with positioning nipples fixed at intermediate points of the cables and stop nipples at each end of each cable. A plurality of elastic anti-skid members are provided having a safety hook on each end. The hook at each end of each anti-skid member is attached to one of the cables at a point adjacent a nipple and a hook of one of the members connects the end of a cable together at a stop member.