Summary: Following the works of A.G. van Asch and F. van der Blij [Bull. Belg. Math. Soc. - Simon Stevin 2, No. 5, 573–589 (1995; Zbl 0847.51016)], we show that the horn angles introduced by Euclide by superreal numbers as Tall defined them. We deduce from this the possibility to estimate, on the one hand, the ratio of the measures of a horn angle and of the mixed angle formed by a spiral of Archimede and, on the other hand, the ratio of the measures of two horn angles.