Dissertation third : exhibiting a general view of the progress of chemical philosophy, from the early ages to the end of the eighteenth century / by William Thomas Brande.

  • Brande, William Thomas, 1788-1866.
Date:
1818
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Licence: Public Domain Mark

Credit: Dissertation third : exhibiting a general view of the progress of chemical philosophy, from the early ages to the end of the eighteenth century / by William Thomas Brande. Source: Wellcome Collection.

Provider: This material has been provided by the Harvey Cushing/John Hay Whitney Medical Library at Yale University, through the Medical Heritage Library. The original may be consulted at the Harvey Cushing/John Hay Whitney Medical Library at Yale University.

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    that the iron was converted into the black brittle sub- stance, called martial elhiops by the old cbemisls, and that 100 grains of iron absorbed about 100 cubical inches of the gas, and increased 35 grains in weight. Hence martial etbiops appeared to be a compound of oxygen and iron. Phosphorus was burned in the same manner. There was a considerable absorption of the gas, and it appeared that the phosphorus had sustained a precisely equivalent increase of weight. The general conclusions deduced from these experi- ments were bold, but incorrect. It was assumed that oxy- gen must be present in all cases of combustion ; that the base of the gas always unites to the burning body, and that the heat and light essential to the aeriform state of the oxygen are consequently thrown off, or rendered sen- sible. With regard to the necessity of the presence of oxygen, it may be remarked, that the cases are very numerous, in which bodies burn, and vividly too, indepen- dent of that principle, although it is perfectly true that, in the generality of instances, oxygen feeds the flame. It is, therefore, more philosophical, to consider combus- tion, or the evolution of heat and light, as a general re- sult of intense chemical action, and as ensuing in all cases where it may be conceived that the corpuscles of bodies are thrown into violent motion, than as depending upon the presence of any distinct substance, or ensuing from the mutual actions of any appropriate forms of matter. But farther; there are many cases in which oxygen unites to bodies, without the evolution of heat and light, as during the gradual change of some of the metals by ex- posure to air. And there are numerous instances in which vehement combustion ensues, not only where there is no condensation of air, but where gaseous matter is