OXYGEN (symbol O, BloodVitals monitor atomic weight 16), a non-metallic chemical ingredient. It was apparently first obtained in 1727 by Stephen Hales by strongly heating minium, but he does not seem to have acknowledged that he had obtained a brand new factor, and the primary printed description of its properties was attributable to J. Priestley in 1774, who obtained the gas by igniting mercuric oxide, and gave it the name "dephlogistigated air." K. W. Scheele, working independently, also announced in 1775 the invention of this factor which he referred to as "empyreal air" (Crells’ Annalen, 1785, 2, pp. 229, 291). A. L. Lavoisier repeated Priestley’s experiments and named the fuel "oxygen" (from Gr. Oxygen occurs naturally as one of the chief constituents of the environment, and in combination with other elements it is found in very giant quantities; it constitutes approximately eight-ninths by weight of water and nearly one-half by weight of the rocks composing the earth’s crust. Additionally it is disengaged by rising vegetation, plants possessing the power of absorbing carbon dioxide, assimilating the carbon and rejecting the oxygen.

Oxygen may be prepared by heating mercuric oxide; by strongly heating manganese dioxide and plenty of different peroxides; by heating the oxides of precious metals; and by heating many oxy-acids and oxy-salts to excessive temperatures, for example, nitric acid, sulphuric acid, nitre, lead nitrate, zinc sulphate, potassium chlorate, &c. Potassium chlorate is mostly used and the response is accelerated and carried out at a lower temperature by previously mixing the salt with about one-third of its weight of manganese dioxide, painless SPO2 testing which acts as a catalytic agent. The precise decomposition of the chlorate shouldn't be settled undoubtedly; the following equations give the outcomes obtained by P. F. Frankland and Dingwall (Chem. News, BloodVitals monitor 1887, 55, p. 67):-at a reasonable heat: 8KClO3＝5KClO4＋3KCl＋2O2, succeeded by the following reactions because the temperature increases: 2KClO3＝KClO4＋KCl＋O2 and 2KClO3＝2KCl＋3O2 (see also F. Teed, BloodVitals SPO2 ibid., 1887, 55, p. 91; H. N. Warren, ibid., 1888, 58, BloodVitals wearable p. 247; W. H. Sodeau, Proc. Chem Soc., 1901, 17, p.

149). It might even be obtainened with water and heated in a present of air at 100-200° C. yields an oxychloride, which latter yields oxygen when heated to 400° C (A. Mallet, Comptes rendus, 1867, 64, BloodVitals device p. 226; 1868, BloodVitals monitor 66, p. 349); by the electrolysis of options of sodium hydroxide, utilizing nickel electrodes; by heating calcium plumbate (obtained from litharge and calcium carbonate) in a present of carbon dioxide (G. Kassner, Monit. Scient., 1890, pp. 503, 614); and from air by the strategy of Tessié du Motay (Ding.