Our recently acquired Youden null-point pH meter. The Moir electrode system, minus one of the salt bridges, is to the left and a circa 1940 bottle of quinhydrone is displayed between it and the meter.

Issue 33 describes a recently acquired compact pH meter from the 1940s that uses a quinhydrone electrode, rather than either a hydrogen electrode or a standard glass electrode.

Click here for all other issues of Notes from The Oesper Collections and to explore the Jensen-Thomas Apparatus Collection.