What is "ebullioscope"

Ebullioscope \E*bul"li*o*scope\, n. [L. ebullire to boil up + -scope.] (Phys. Chem.) An instrument for observing the boiling point of liquids, especially for determining the alcoholic strength of a mixture by the temperature at which it boils.

n. (context physics English) An instrument used to measure the boiling point of liquids

An ebullioscope (from the Latin ēbullīre (to boil) + -scope) is an instrument for measuring the boiling point of a liquid. This can be used for determining the alcoholic strength of a mixture, or for determining the molecular weight of a non-volatile solute based on the boiling-point elevation. The procedure is known as ebullioscopy.

The first ebullioscope was invented in 1838 by Honoré Brossard-Vidal, and was used for measuring alcoholic content. The advantage of this method was that the boiling point is relatively insensitive to other components such as sugars. Older alcoholimeters were based on measuring the density, which is more sensitive to the presence of other solutes.See:

• P. Doré. Leçons de chimie élémentaire appliquées aux arts industriels …, (Paris, France: Victor Dalmont, 1857), pages 323-325.
• Brossard Vidal, Observations sur les instruments de l'administration et du commerce pour reconnaître la richesse alcoolique des liquides spiritueux (Paris, France: A. Henry, 1842)
• Ad. Chambon (1845), "Considérations sur l'Ebullioscope alcoométrique de MM. Vaille et Vidal Brossard," Répertoire des Travaux de la Société de Statisque, 8 : 93-98.
• Louis-François Desbordes and Honoré Brossard-Vidal, "alcoomètre Vidal," French patent 415 (filed: November 23, 1844; issued: June 18, 1845), Bulletin des lois du Royaume de France (1846), 9th series, vol. 31, page 72.See:
• E. Malligand and E. Brossard-Vidal (May 25, 1874) "Sur l'ébullioscope Vidal," Comptes rendus, 78 : 1470-1471.
• [Anon.] (July 17, 1874) Chemical Notices from Foreign Sources: "Vidal Ebullioscope," The Chemical News and Journal of Physical Science, 30 (762) : 30.

A later version was built by the French chemist François-Marie Raoult, but the difficulty of determining the exact temperature was overcome by the invention of the Beckmann thermometer by Ernst Otto Beckmann in 1887. This improvement made the ebullioscope a standard apparatus to determine the molecular weight of substances in solution by using the ebullioscopic constant of the solvent.