Medical Hydrometer
Ullapool Museum
This small device is actually a urinometer. It was used for many years to measure the specific gravity of human urine. This tells us urine density which is affected by what is dissolved in urine, including the salts or protein.
There are many illnesses and conditions that can be detected from analysing urine samples, but this device would help a GP to recognise when the kidneys were not functioning correctly or if the patient were suffering from dehydration. Nowadays, it has now been replaced by more accurate and comprehensive laboratory tests of each chemical in blood and urine.