F. BARKER & SON
POCKET DAMP DETECTOR
Museum condition - works perfectly - Barker triangular hallmark on dial - blued steel sweep indicator - adjustment knob on reverse (turn cross to zero instrument) Japan lacquer in excellent condition - Morocco leather case with velvet lining in excellent condition
Instrument diameter, excluding neck and bow: 37mm
QUOTATION FROM BOOK "TRADE MARK LONDON"
The damp detector is a very simple instrument. A blued steel needle is connected directly to a "hair" of catgut, which acts as the spindle, that is threaded through a support tube and fixed at the far end of the tube from the needle with a small wooden wedge and a drop of tar. The tube has an opening half way down to expose the catgut "hair" to ambient humidity, which enters the case through the multi-perforated back. Changes in relative humidity cause a torsional movement of the catgut, which causes the needle to move in a circular sweeping movement around the calibrated dial. The needle can be "zeroed" or calibrated by revolving the cross-shaped part on the back of the case.
The damp detector was advertised as a means for testing hotel beds for dampness, and as a means of proving that dampness to unscrupulous hotel owners and managers, who were famous for suggesting that the dampness was purely a figment of the traveller's imagination. For the first time, the traveller was able to offer "scientific proof" and to insist on another room with a dry bed.