Galileo 5 Globe thermometer

This distinctive ornamental (but functional!) thermometer utilises 17th century astronomer Galileo Galilei's discovery that the density of liquids varies with temperature.

Carefully weighted glass globes are suspended in a liquid-filled tube, where they sedately sink or float as the surrounding air gets hotter or colder.
The temperature is indicated by the engraved brass tag on the lowest floating globe.
Useful for forecasting the weather and a lovely desktop curiosity.