Oxygen principles

We have also seen that Lavoisier identified dephlogisticated air as the principle of acidity, and accordingly renamed its material substance oxygen. And in parallel to Macquer s phlogiston, Lavoisier s oxygen principle was known to be infallibly present in acids, but its presence did not necessarily confer acidity on all bodies that contained it. Let us briefly examine the use of principles that was so common in chemical descriptions of the seventeenth and eighteenth centuries, and compare it with Lavoisier s use of the principle of acidity. 

Mr. Kirwan, in the defects that he takes exception to in my table of the affinities of the oxygen principle with various substances, does not judge me more severely than I have judged myself, but he should be warned that all the objections he makes against this table I have made before he did, and perhaps in a stronger manner. ... 

The action of metal on the oxygen principle of acid and on that of water... 

But in which order are found all these combinations. What are the degrees of affinity that the oxygen principle has with these different substances. According to which laws are they excluded or precipitated. This is the object that I propose to examine in this memoir the one that I have had in view from the beginning of the work that I have explained to the Academy the one for which I have never ceased to assemble the material for several years. ... 

Third, affinity was an important, if understated, issue in the debate. Kirwan found Lavoisier s table of the affinities of oxygen liable to numerous objections because it ran counter the experimental facts. The critical factor was the affinity of the principle of heat with the oxygenous principle, which occupied 21st place in Lavoisier s table. Of the 20 other substances that occupied higher places, Kirwan protested, none of the first 19 united with the oxygenous principle at the common temperature of the atmosphere. Nitrous air, the only substance that united with the oxygenous principle at every temperature, occupied the 20th place. 

The forces acting in the dissolution of a metal in an acid are the action of heat, which (i) tends to separate the molecules (molecules) of water and reduce it to vapour, (a) tends to disunite the principles of nitric acid and convert it into gaseous substances, (3) acts on the constituent principles of water, (4) diminishes the affinity of aggregation of a metal and tends to separate its parts (5) the reciprocal action of nitrous gas and the oxygen principle, (6) their combined action on water, (7) the action of the metal on the oxygen principle of the acid and on that of the water, and (8) the action of the acid on the metal, or rather on the metallic calx. 

Lavoisier says the oxygenous principle combined with the matter of fire, of heat and of light, forms the purest air. This is very probable but not rigorously demonstrated — it may not be susceptible of this. Combined with carbon it forms chalky acid (acide crayeux) or fixed air, with sulphur vitriolic acid, with nitrous air nitric acid, and with phosphorus phosphoric acid. It is... 

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