Copy 1, Volume 1

A system of chemistry ... / [Thomas Thomson].

  • Thomas Thomson
Date:
1804
Catalogue details

Licence: Public Domain Mark

Credit: A system of chemistry ... / [Thomas Thomson]. Source: Wellcome Collection.

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    previously empty his lungs, he was able to breathe it for Chap. If. about a minute without much inconvenience *. When much diluted with common air, it may be breathed without injury. 4. If a phial be filled with hydrogen gas, and a light- Combust- ed candle be brought to its mouth, the gas will take fire, and burn gradually till it is all consumed. If the hy- drogen gas he pure, the flame is of a white colour ; bat if the gas holds any substance in solution, which is oft- en the case, the flame is tinged of different colours, ac- cording to the substance. It is most usually reddish, because the gas holds in solution a little charcoal. A red hot iron likewise sets fire to hydrogen gas. From my experiments it follows, that the temperature at which the gas takes fire is about iooo°. If pure oxygen and hydrogen gas be mixed together, they remain unaltered •, but if a lighted taper be brought into contact with them, or an eledlric spark be made to pass through them, they burn with astonishing rapidi- ty, and produce a violent explosion. If these two gases be mixed in the proportion of one part in bulk of oxy- gen gas and 2.527 parts of hydrogen gas, or, more accu- rately, 85 parts by weight of oxygen gas and 15 ofhy- Explodes drogen gas, they explode over water without leaving gengasj any visible residuum; the vessel hr which they were and*or*ns contained (provided the gases were pure) being com- pletely filled with water. But if the explosion be made in a close vessel, there is always found instead of them a quantity of water exactly equal to them in weight. This water must be composed of these two gases; fo r it did not previously exist in the vessel, and no other
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