I am trying to find out more about the density (or specific gravity SG) of the glass used by various manufacturers in the Midlands area in the 1840 - 1900 period. My reason is to try and track down the probable makers of a couple of designs of paperweight.
I have measured the SG of over 150 Old English paperweights in the last couple of years, and know the typical ranges of SG for paperweights believed to be made by Richardson, Arculus / Walsh Walsh (1900 onwards), Bacchus, Islington (and also 1950-1970 Whitefriars). I have measured a couple of Richardson family bequest items in Broadfield House, and these are consistent in value with their paperweights.
I have seen some SG figures for uranium glass published by Barrie Skelcher in 1998, but those are the only public domain measurements I have managed to track down.
Does anyone know of published SG measurements for Midlands manufacturers pieces made 1840-1900, particularly from the following:
George Bacchus & Sons
Webb & Sons
Stevens & Williams
John Walsh Walsh
Davis, Greathead & Green
Rice Harris / Islington
Boulton & Mills
Any help gladly received!