Schelter und Giesecke Grotesks

In the course of the XIX th century, there were two countries that launched the new production of sans serif typefaces: England and Germany. The most famous German foundry was Liepzig-based Schelter und Giesecke which gave grotesk typefaces from 1825. Other German foundries like Berthod and Stempel will produce grotesks but at the end of the century.

The only references of S&G grotesks belonged to the last quarter of the XIX th century: Schelter Grotesk, Schlanke Grotesk, Breite Grotesk.
Designer Nick Curtis attempted to reproduce the style of these typefaces.

1. Is there any leads to pinpoint the very first German grotesks from 1825?