The first thermometer of this kind was invented in 1817 by Abraham-Louis Breguet (1747-1823), a watchmaker, engineer, inventor, physicist, and businessman originally from Neuchâtel, Switzerland, after establishing his watchmaking shop in Paris, France in 1775.

This device was used in the physics and chemistry laboratory of the Séminaire Saint-Joseph from 1886 to 1960.

Thanks to a generous donation from the Alumni, the Seminary procurator at the time, Father Joseph Élie Raymond Bernard Caisse (1850-1899), was able to purchase this instrument in Paris in the summer of 1886, as well as several others, from Eugène Ducretet (1844-1915), who founded Ducretet et Cie. in 1864. This company specialized in the manufacture of a whole range of scientific instruments.

Somewhat complex, but above all fragile, this type of device is used to measure air temperature. The spiral located vertically in the centre is made of three very narrow overlapping blades: one platinum, one gold, and one silver. They are welded along their entire length and thus form a long, thin ribbon. This ribbon is wound up in a helix shape, the upper portion of which is attached to a support. Under this spiral, a copper needle is placed, under which a horizontal dial indicates the temperature measurements. A variation in temperature causes the needle to move.

The whole apparatus is placed under a glass bell.

Musée Pierre-Boucher Collection
2002 319 I.4-1