The discovery of oxygen, part 1 : experiments / by Joseph Priestley, LL.D. (1775).

  • Priestley, Joseph, 1733-1804.
Date:
1894
Catalogue details

Licence: Public Domain Mark

Credit: The discovery of oxygen, part 1 : experiments / by Joseph Priestley, LL.D. (1775). Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    nature of this kind of air, though very gradually, but was led by it to the complete discovery of the constitution of the air we breathe. Till this ist of March, 1775, I had so Httle suspicion of the air from mercurius calcinatus, &c. being whole- some, that I had not even thought of applying to it the test of nitrous air; but thinking (as my reader must imagine I frequently must have done) on the candle burning in it after long agitation in water, it occurred to me at last to make the experiment; and putting one measure of nitrous air to two measures of this air, I found, not only that it was diminished, but that it was diminished quite as much as common air, and that the redness of the mixture was likewise equal to that of a similar mixture of nitrous and common air. After this I had no doubt but that the air from mer- curius calcinatus was fit for respiration, and that it had all the other properties of genuine common air. But I did not take notice of what I might have observed, if I had not been so fully possessed by the notion of there being no air better than common air, that the redness was really deeper, and the diminution something greater than common air would have admitted. Moreover, this advance in the way of truth, in reality, threw me back into error, making me give up the hypo- thesis I had first formed, viz. that the mercurius calcinatus had extracted spirit of nitre from the air; for I now con- cluded, that all the constituent parts of the air were equally, and in their proper proportion, imbibed in the preparation of this substance, and also in the process of making red lead. For at the same time that I made the above mentioned experiment on the air from mercurius calcinatus, I Hkewise observed that the air which I had extracted from red lead, after the fixed air was washed out of it, was of the same nature, being diminished by