![](https://coimages.sciencemuseumgroup.org.uk/519/997/large_thumbnail_1990_5036_5040__0001_.jpg)
'Hall Mark' Continuous Contact Electric Copier
- maker:
- B J Hall and Company Limited
"Hall Mark" continuous contact electric copier patent No. 170967 made by B.J. Hall & Co. Ltd., London, c. 1925.
"Hall Mark" continuous contact electric copier patent No. 170967 made by B.J. Hall & Co. Ltd., London, c. 1925.