Vintage Glass Lamp Shade

I have come across this pumpkin shaped glass lamp shade which appears to have some age to it
It has some lettering on it, and I wondered whether anyone could assist in identifying the maker and its age.
It is 23cm across and 7cm deep

All i know is that DRP stands for "Deutsches Reich Patent" and D.R.G.M. stands for "Deutsches Reichsgebrauchsmuster". So it's German and probably has a date between 1891 to 1952. Really difficult to make out the mark below that, looks like it starts with an "S".

Thank you so much, that is very interesting