Abstract: The apparatus for measuring the viscosity of liquids comprises an inclined viscosimetric tube (1) enclosing a ball (3). A device is provided for measuring the duration of fall of the ball (3) in the tube (1). An electromagnet (8) adjacent the tube (1) has poles (9) which set up along the tube (1) a gradient of a magnetic field allowing the automatic rising of the ball (3). The apparatus is used mainly for measuring the viscosity and the time of the coagulation of blood.