New experiments upon the combustion of well-dried carbon monoxide and oxygen mixtures.—Part I

Abstract

In the year 1880, H. B. Dixon (in repeating Bunsen’s experiments on the division of oxygen between carbon monoxide and hydrogen, when both are present in excess) discovered that a mixture of carbon monoxide and oxygen, dried by long contact with phosphoric anhydride, would not explode when sparked in the usual way in a eudiometer over mercury, although the presence of a trace either of moisture or of any gas containing hydrogen at once rendered the mixture explosive.* In 1883, H. B. Baker, working in Dixon’s laboratory at Balliol College, Oxford, found that purified charcoal, when heated to redness in carefully dried oxygen, burned with extreme slowness and without flame, yielding principally the monoxide, the proportion of the dioxide formed varying inversely with the degree of dryness of the system. He also proved that highly purified sulphur or phosphorus may be repeatedly distilled in an apparatus filled with carefully dried oxygen, without any combustion occurring, although the admission of a mere trace of moisture immediately caused a vivid burning. In subsequent years Baker proved that a large number of gaseous inter­actions are at least greatly assisted, if they are not actually conditioned, by the presence of moisture. Thus, (1) a mixture of hydrogen and chlorine, well dried by long contact with phosphoric anhydride, does not explode on exposure to sunlight as does an undried one ; (2) ammonia and hydrogen chloride, when similarly dried, do not combine when mixed in the cold ; whilst (3) thoroughly dried electrolytic gas, free from hydrocarbon impurity, may be heated to redness, or exposed to ultra-violet light, without any measurable formation of water occurring. Such experiments undoubtedly proved that the removal of moisture from certain gaseous systems increases in an extra­ordinary degree their resistance to chemical change, although they can hardly be said to have proved, as is sometimes supposed, that the presence of moisture is absolutely essential to chemical change in such cases.