Instrument	:	Hydrostatic level (flesjeswaterpas)
Manufacturer	:	unknown
Country of origin	:	Possibly the Netherlands
Manufacturing year	:	Mid 20th century

I've obtained this hydrostatic level in 2008. The instrument is probably of Dutch origin. This is slightly less basic than the water bottle level; two communicating containers of water connected by a hose. Both bottles have a scale with a 14 centimetres range. They were used at Corus (at that time 'Hoogovens') for shaft alignment and were already in use some 40 years ago. Roughly 20 years ago they were discarded and subsequently taken home by one of the employees. It was from the latter that I got hold of them.