Dephlogisticated air Oxygen

Joseph Priestley found that the constituent of the atmosphere which restores the bright red color to the dark blood is dephlogisticated air (oxygen) (202). Although Fourcroy and Vauquelin believed that the iron in the blood was combined as a phosphate, it is now known to be present in a far more complex compound, hemoglobin (205). M. O. Schultze found that analyses of hemoglobins of different species yielded concordant values of 0.335 per cent of iron (206). 

As early as 1771 Joseph Priesdey noticed that this process purified the air, and in 1778 he identified the gas as dephlogisticated air (oxygen) (40). I have been so happy, said he, as by accident to have hit upon a method of restoring air which has been injured by the burning of candles, and to have discovered at least one of the restoratives which nature employs for this purpose. It is vegetation.. . . Finding that candles would bum very well in air in which plants had grown a... 

In both cases, calxes of copper remain, so it is clear that the phlogiston has been carried off in flammable air in the first case and in nitrous air in the second case. Now, in comparing flammable air and nitrous air, it is clear using eudiometry that each contains the same quantity of phlogiston since they each react with the same quantity of dephlogisticated air (oxygen) ... 

When Cavendish sparked his inflammable air with Priestley s dephlogisticated air (oxygen), he found that water was formed. 

In some miscellaneous observations , a quantity of air was made by heating saltpetre, and in it a candle burned just as in common air , or not only burned, but the flame was increased, and something was heard like a hissing, similar to the decrepitation of nitre in an open fire . Priestley, as he later recognised," had here obtained dephlogisticated air (oxygen) before November, 1772. 

To render this more explicable, let us suppose P to be an ultimate particle of phlogisticated air [nitrogen], which attracts dephlogisticated air with the force of 3 let a be a particle of dephlogisticated air [oxygen], whose attraction to P we will suppose to be 3 more, by which they unite with the force of 6 the nature of this compound will be hereafter explained. 

Iron is not affected by dry dephlogisticated air (oxygen) and it appears, that iron has no effect on air in a common temperature, but that it is the water which is decomposed, and that the dephlogisticated air and inflammable air unite at the very instant of its liberation, and re-compose water . Higgins says Mrs. Fulhame boasts very much of her discovery , but cautiously omitted mentioning the work from which she borrowed her ideas . But what he said in 1799, that the fair author had probably not read his book, is more correct. 

Crawford concluded that the specific heat ( capacity for containing heat ) of dephlogisticated air (oxygen) is 4 6 times that of common air. He also concluded that the capacities of bodies for containing heat are diminished by the addition of phlogiston, and increased by the separation of this principle . The ratios of the specific heats of the calces (oxides) of metals to those of the metals were found to be (calx metal) tin, 14-7 10 4, iron 8 3 1, lead 19 9 14 7, antimony ii-6 4-5. 

His other chemical research was directed at what was then called nitrous air (nitric oxide) and dephlogisticated air (oxygen). In 1779 he observed that oxygen s solubility in water is greater than that of air, and in 1780 he determined the nature of water gas (a mixture of hydrogen and carbon monoxide). In 1777 he discovered carbon s ability to absorb gases. 

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