In December 2016 museums volunteers found these two large valves about 12 inches tall to the top of the outlet, with two and a half inch V-thread outlets were among hundreds of items put in storage.

We asked many people what these valves could be.

No one knew. Then Dennis Scott, (Aberdeen Fire Brigade Historian) pointed us in the direction of Plate 6,  Figure 1 in the book, “On the Construction of Fire-Engines and Apparatus” written in 1830 by James Braidwood, Master of Fire-Engines, Edinburgh.

The drawing shows a FIRE COCK (K) (Hydrant) attached to the WATER MAIN (B).

This book also contains an 1830 inventory of Edinburgh Fire-Engine Establishment which lists the number and size of fire-cocks and notes that Braidwood kept “Two spare fire-cocks for repairs.”

It may be that since 1830, repairs have not been required !

Further searching discovered a two and a half inch V-thread Distributor (standpipe) which fits the fire-cocks. Originally used to connect to hose with V-thread couplings this standpipe was later used to connect to hose with instantaneous couplings as it is fitted with a V-thread to Instantaneous Coupling Adaptor.  (Note that Edinburgh Fire Brigade ran out hose with the male coupling to the fire.)