DUFAY (DU FAY), CHARLES FRANCOIS DE CISTERNAY.

Memoire sur les Barometres lumineux.

(Paris, L'Imprimerie Royale, 1725). 4to. Without wrappers. Extracted from "Mémoires de l'Academie des Sciences. Année 1723". Pp. 295-306.

First appearance of Dufay's first work.

"His first academic paper (1723), on the mercurial phosphorus, already displayed the characteristics which distinguished his later work: full command of earlier writings, clear prescriptions for producing the phenomena under study, general rules or regularities of their action, thorough study of possible complications or exceptions, and cautious mechanical explanations of a Cartesian flavor. This "phosphor" - the light sometimes visible in the Torricelli space when a barometer is jostled - much perplexed the physicists of the era, primarily because it did not always occur under apparently identical conditions. Dufay found that traces of air or water vapor occasioned the failures, which could be entirely eliminated with a technique of purification taught him by a German glassmaker. He explained the light in terms of Cartesian subtle matter squeezed from the agitated mercury; although he knew the work of Francis Hauksbee (the elder), he suggested no connection with electricity."(DSB).

Order-nr.: 46601