Thermoscope

[3] The device was built from a small vase filled with water,[4] attached to a thin vertically rising pipe, with a large empty glass ball at the top.

Changes in temperature of the upper ball would exert positive or negative pressure on the water below, causing it to rise or lower in the thin column.

[3] Galileo's own work with the thermoscope led him to develop an essentially atomistic conception of heat, published in his book Il Saggiatore in 1623.

[9] It was Drebbel who announced in the early 17th century one of the earliest or possibly the first prototype, which was filled with air and blocked by water containing a little aqua fortis to prevent it from freezing and being discolored.

[9] Ferdinando II de' Medici, Grand Duke of Tuscany personally made a further improvement by introducing the use of a colored alcohol, so that the material responding to heat was now liquid instead of gas.