In article ,
Richard J Kinch wrote:

I'm wanting to revive a vintage Taylor-Hobson Talyvel inclinometer:

http://www.truetex.com/talyvel.jpg

This specimen calls for what appears to be a pair of absent
"Mallory battery SKB-830" units for power, which comes up unknown on a Web
search. From the enclosure and connections it looks like these might have
each been a cylinder about the size of two C cells in series with snap tabs
similar to a 9-volt battery but larger. The battery test meter appears to
be testing for about 6 volts. Maybe 5.4 volts if it was four mercury cells
at 1.35 volts each.

Any ideas on what this battery might have been? All I can determine is
that the Mallory SKB batteries were the mercury type developed during WWII
(http://www.duracell.com/procell/about/background.asp).

The company that made the Talvel still exists, so I would ask them.

Joe Gwinn