A history of chemical theory from the age of Lavoisier to the present time / by Ad. Wurtz ; translated and edited by Henry Watts.

Date:
1869
Catalogue details

Licence: Public Domain Mark

Credit: A history of chemical theory from the age of Lavoisier to the present time / by Ad. Wurtz ; translated and edited by Henry Watts. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    body subjected to the action of fire becomes decom- posed, and tbat whicb remains after tbe combustion was previously one of tbe elements of tbe combustible body. Thus the ashes of metals, or metallic calxes, were contained in the metals themselves in combina- tion with phlogiston. This latter may be restored to them by heatiug them with substances rich in phlogiston, such as carbon, wood, or oU. Calcine litharge with powdered charcoal, and you will recover metallic lead. The phlogiston will leave the charcoal to iinite with the litharge, and form with it the revi- vified lead. The triumph of a theory is to embrace the greatest number and the greatest variety of facts. Now the theory of phlogiston was equally applicable to two opposite orders of phenomena, and united them by a theoretical bond. Bringing together the phenomena of combustion, and the facts relating to the calcination of metals in the air, and their conversion into metallic calxes, it explained both the one and the other; and, moreover, gave a very simple interpretation of the phenomena of reduction, the inverse of the former. But what was the part played by the air in com- bustion ? On this point the theory was mute ; and nevertheless observation had gone before it, and had long before directed attention to the importance of this condition of the change. Jean Rey, physician, of Perigord, had caiight a glimpse of it as early as
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