The doctrine of phlogiston established, and that of the composition of water refuted / by Joseph Priestley.

  • Priestley, Joseph, 1733-1804.
Date:
1800
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Licence: Public Domain Mark

Credit: The doctrine of phlogiston established, and that of the composition of water refuted / by Joseph Priestley. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    Mr. Chaptal fays, about B per cent, ip being convert- ed into precipitate, an ounce of mercury muft contain 362 ounce meafures of inflammable air, or rather the phlogifton that enters into it. An ounce of lead, I have ftiewn, requires 108 ounce meafures of inflam- mable air, an ounce of bifmuth 185. of tin 377, of copper from verditer 403, and of iron 890- That mercury revived either by mflammable air or in clofe veflels has the fame properties will not be de- nied ; and if fo, it muft confift of the fame principles, and m the fame proportions, or nearly fo. I am there- fore inclined to think, improbable as it may apptar, that the fame principle which is eifential to the cunfti- tution of inflammable air, that is phlogifton, paffes -from the fewel thro' the glafs when the calx is revived by heat in a glafs veird. There is, however, only the choice of this diffi- culty, and of that of an ounce of mercury containing 'either 362 ounce meafures of inflammable air (that is 'the phlogifton in it) or none at all. It is not denied that light and heat, both of which are allowed to be fubjlances, tho' the weight of them cannot be afcertain- ed, pafs thro'glafs. They both have certain proper- ties, and are transferable from one fubftance to ano- •'ther, accordi^^g to their known affinities. And why may not this be the cafe with phlogijlon alfo. Light certainly paffes thro' glafs ; and is known to give to fome fubftances colour, fmell, and tafte, which have ufually been alcribed to phlogifton. That it does not revive the lead in pafling thro' the hot flint glafs is no fufficient ohje6tion. For the fame fubftances indiffer- ent combinations, and in diff'erent ftates, have diff^er- ent properties. The doftiine of chemical affinities has yet many difficulties attending it, and it requires ' tht niceft dif'crimination of circumflances to make con- fiftent tables of them. However, I can only Dropofe Jath, let others account for them in the btft manner that