Abstract: The invention relates to an apparatus and a method for direct addition of solid ferrocene to fuels. The liquid addition or fortification of fuels with ferrocene is known. The new apparatus and the new method enable an addition of solid ferrocene to fuels. The apparatus according to the present invention comprises a grinder being connected to a fuel conduit or a fuel tank, said grinder being filled with solid ferrocene. The apparatus further comprises a step motor being coupled to the grinder and includes a control means for said step motor. With respect to the method of the present invention it is proposed to measure the amount of fuel flowing through a fuel conduit, to determine the required amount of ferrocene therefrom and to add the so determined amount of ferrocene to the amount of fuel by actuating the grinder at the corresponding number of revolutions.