USA 1878 Portable model for paper strip

The 1878 US patent model - owned today by Flavio Mantelli. Photo: Flavio Mantellig.
The drawing shows which part of the writing ball the patent model is illustrating. Foto: Flavio Mantelli.
Flavio Mantelli's collection of Malling-Hansen items. It includes both a writing ball of the 1878 model and a porcelain practicing model. Foto: Flavio Mantelli.