This is a traditional cache on a footpath that runs close to the site of the former station at Ashburton. The background image dates from around 1900 and shows the extent of the railway yards that once brought goods and passengers to the town.
The railway station at Ashburton was the terminus of a branch line running from Totnes. There is a heritage railway that runs as far as Buckfastleigh, the trackbed between there and Ashburton is no longer since the town was bypassed in the 1970s.
You are looking for a small test tube which is not at ground level.