TitleDecade resistance box, H. Tinsley & Co, No. 1718About this objectDecade resistance box measures electrical resistance to determine if a circuit is leaking current to the earth, thereby not transmitting signal correctly. This device features two dials that adjust resistance in increments of ten – hence the name ‘decade’ – and an earth terminal included on the housing. In telegraph systems, decade resistance boxes were used to detect faults that could weaken or interrupt signal transmission over submarine cables.
Established in 1904, Henry Tinsley and Co. Ltd. manufactured scientific instruments and electrical measuring equipment for laboratories and telegraph engineers. The company, now trading as Tinsley Instrumentation Ltd, continues producing decade resistance boxes, though no longer in this type of wooden case.
The inscription ‘O.T.T / PADN’ on the housing likely refers to the Overseas Telecommunications Commission (Australia) – Australia’s international telecommunications carrier from 1946 – which operated a terminal in Paddington in 1962. Object No.99.76CreatorH. Tinsley & Co Inscriptions & marksA small plaque on the top reads ‘EUREKA/B.A. OHMS/AT 20°C’; two dials labelled ‘Ten Thousands’ and ‘Thousands’ respectively; ‘H. TINSLEY & CO. LONDON S.E. No. 1718’ on the bottom.
‘O.T.T’ printed in gold on the front of the wooden box. DimensionsH: 119mm
W: 253mm
D: 164mmPlace madeLondonSourceLa Perouse MuseumOn displayYesTypeMuseum objectsOrganisations (Detailed entries)La Perouse Museum (La Perouse, N.S.W.)ThemesScience and communication
H. Tinsley & Co , Decade resistance box, H. Tinsley & Co, No. 1718. Randwick City Council, accessed 20/03/2026, https://ourstory.randwick.nsw.gov.au/nodes/view/12392
