**Read entire English excerpt ****here**.

Imagine being eleven years old. And imagine you are invited to hold a lecture on the forth geometrical dimension at Harvard in front of a horde of math and physic university professors. That’s what happened to the young William James Sidis in 1910. Here is how he started:

“My own definition of the fourth dimension would be that it is an Euclidian space with one dimension added. It is the projection of the figures of the third dimension into space. The third dimensional figures, such as the cube, are used as sides of the figures of the fourth dimension, and the figures of the fourth dimension are called configurations. It is not possible to actually construct models of the figures of the fourth dimension, or to conceive of them in the mind’s eye but it is easy to construct them by means of Euclid’s theorem. In this theorem, F equals the faces of the figures, S equals the sides, V equals the vertices, and M equals the angles. The theorem is that F plus S equals V plus M….”