Thermometers

Four decorative thermometers and their carved backboards. In each case, the bulb is in the centre of the stem, which spirals out from it. In the top two this is an oval [left as viewed] and a circle [right]; in the bottom this is a triangle [left] and a star [right].

Plate 15 from a German translation of Joachim d’Alence’s Tractatus de barometris (Ludwig Bourgeat, Mainz, 1688), an early account of meteorological instruments including barometers, thermometers and hygrometers.

Joachim d’Alence (1640-1707) French astronomer and physician.