Abstract: Method of measuring the time of coagulation of samples of fluid products such as, for example, samples of blood plasma, wherein the dose of liquid substance to be analyzed is introduced into a small cup (1) the base (1a) of which is shaped to serve as a circular rolling path (1b) for a ball (2) disposed in the lower part of the cup which is actuated with a non-rotary circular movement be means of an eccentric (3-3a) causing a rotation of the ball in a circular path in the base of the cup. The gradual slowing and/or halting of the rotary movement of the ball caused by the thickening or coagulation of the sample of the medium or liquid substance contained in the cup, for example following the introduction of a reactant, is ascertainable visually or, preferably, by any suitable automatic detection system.

Abstract: An apparatus for measuring the time taken for a change to occur in the physical state of a material or medium, such as the time of appearance of a clot in a blood sample, includes a jar whose bottom may serve as a circular track for a ball, a ball able to roll around the track, a support for the jar maintaining the bottom of the jar and track in a plane inclined in relation to the horizontal plane, a means for rotating the support and jar whereby the ball remains at the lowest point of the track when the material is in the liquid state but is carried around the track by the more viscous material when that has changed its state, and a means of detecting the movement of the ball.