The alchemists used the terms fermentation, digestion and putrefaction indiscriminately; any reaction in which chemical energy was displayed in some form or other - such, for instance, as the effervescence occasioned by the addition of an acid to an alkaline solution - was described as a fermentation (Lat.
The oxidation of the foreign elements must be very slow, lest the effervescence due to the escape of carbonic oxide from the carbon of the metal throw the charge out of the doors and ports of the furnace, which itself must be shallow in order to hold the flame down close to the charge.
With the rise of Mahommedanism occurred a sudden effervescence of the Arabs, who during some centuries threatened to impose not only their political authority but their civilization and new religion on the whole known world.
At this time rumours were current of disaffection among the Zulu, but this was regarded as the effervescence natural after the war.
Chemistry, as well as mathematics, seems to have been the object of his early attention; and in the year 1690 he published a dissertation on effervescence and fermentation.