I just inherited what I think are a pair of Gauge Glass tubes. My mother gave them to me, they belonged to her father who was an S.A.R. man and worked his whole working life at Islington Works.
As a youngster my mother was told they were out of a Steam Loco boiler and warned of a fate worse than a fate worse than death if she ever broke them so I suspect they left Islington under the newspaper in the bottom of his kit bag. Later my Grandfather and my Father used them with long lengths of hose attached to level my parents block of land in Glenalta before our house was built.
They are 9" long, 16mm OD, 9.4mm ID so walls are thick, 3.5mm (sorry about the switch from Imperial to Metric, I have an Imperial ruler but my Vernier is purely Metric!)
If they are what I think they are then I would like to return them back to SA to be used as spares or whatever. I know that they are not worth much to buy but who knows, if Steamranger or someone else can use them then I would be happy to shoot them over.