Klein then learned about this discussion from Clebsch and wrote the following in a letter to Noether from 17 December 1869:[^8]

> You will perhaps also be interested in what I learned from Clebsch when he was here during the fall vacation. (I really don’t know any more whether I already wrote you this or not.) Kronecker has proved, namely, that a plane curve with arbitrary singularities can always be transformed into one with a single multiple point whose tangents are all distinct. Clebsch then pointed out that one can easily resolve this multiple point into ordinary double points. One views the plane containing the curve as the image of an $F_3$ \[cubic surface\] in such a way that a fundamental point passes into the given multiple point. – This comment of Clebsch appears to me to possess considerable mathematical value. If I’m not mistaken, it allows for a type of extension so that one can immediately reduce arbitrary singularities to ordinary double points.[^9]

One can easily imagine Noether’s astonishment when he read this passage, which not only clearly indicated that Clebsch had found a simple method for reducing the singularities of a plane curve to double points. It also 