Jason Clarke Antiques has dated this Victorian Geissler Tube Apparatus to the 1900s.
This uncommon set is comprised of an ebonised wood base and upstand.
Each Geissler tube has an attached label numbering successively from 1 to 6 and the base and the side of the upstand are also fitted with a connection point.
The cross-vacuum scale demonstration is to show the variations of electric glow discharge when voltage is applied to a set of glass (Geissler) tubes which are gas filled and all have varying levels of vacuum pressure within them. The glow or plasma is created by applying voltage and the requisite pressure within each will denote how strongly or brightly the tube glows. Different gases will also denote which colour glow is achieved.
This example is unnamed although it does look as though some type of label was once applied to the back edge of the base, however, numerous companies such as Max Kohl of Germany are known to have produced them in latter stages of the Nineteenth Century and early Twentieth Century.
Circa 1900
Jason Clarke Antiques has dated this Victorian Geissler Tube Apparatus to the 1900s.
You can view the stock and full dealer information on the Jason Clarke Antiques Profile Page
Late Victorian Geissler Tube Cross Vacuum Scale
