Pole Finding Paper

G.E.C.
POLE FINDING PAPER
For Electrical Works, Wireless Works, Garages, etc.
(Guaranteed All-British Manufacture).
Treble Impregnated & Highly Sensitive. Suitable for all Climates.
Instructions.- Tear off a section of the paper and moisten it with water (or apply moisture from the tongue). The two wires from Dynamo, Mains or Battery should then be pressed upon it for a few seconds, keeping the wires at the same time about ⅛-in apart (for high voltages a ¼ to ½-in apart). The wire that leaves a Red Mark on the paper is the Negative Pole. The wires should be bright and clean when making the test’.

This is essentially blotting paper dipped in a solution of sodium sulphate to which a few drops of phenolphthalein has been added.

A search of the Internet reveals such paper described in a book of 1902 but the actual date of this book is unknown.