Rays of positive electricity and their application to chemical analyses / [Sir J.J. Thomson].

  • Thomson, J. J. (Joseph John), 1856-1940.
Date:
1921
Catalogue details

Licence: In copyright

Credit: Rays of positive electricity and their application to chemical analyses / [Sir J.J. Thomson]. Source: Wellcome Collection.

    214/278 (page 198)
    prolonged until its extremity was only one-half the normal distance from the vertical axis; if there were a line corre- sponding to a carbon atom with three charges, the ordinary carbon line would be prolonged until its distance from the vertical was only one-third of the normal distance ; while a carbon atom with four charges would prolong the ordinary carbon line to within one-quarter of the distance from the axis. Again, the greater the charge the less the intensity, so that a line due to a quadruply charged carbon atom would be accompanied by a stronger line due to a triply charged atom, a still stronger one due to a doubly charged atom, while the normal carbon line would be the strongest of all. Now we do not find any of these characteristics in the case of the X3 line; the carbon line is not prolonged to within one-quarter of the normal distance, and so far from the line being accompanied by a stronger line due to a doubly charged carbon atom, in many cases when the “ 3 ” line is very strong the line due to the doubly charged atom is not strong enough to be detected ; indeed, in some cases the “ 3 ” line is stronger than the normal carbon line. Again, since the gas giving the “ 3 ” line can be detected in the tube long after the bombardment has ceased, if it were carbon with four charges some gas must be formed by the bombardment which gives, when the discharge passes through it, carbon atoms with four charges. Experiments made with a great variety of carbon compounds, introduced directly into the discharge tube, e. g. CH4, C02, CO, C2H4, C2H2, COCl2, CC14, failed to produce this line, so this view of its origin must be abandoned. There is, on the other hand, strong evidence of this line being due to hydrogen. We have seen that under exceptional conditions it can be obtained by sending the discharge through hydrogen without the liberation of gas by bombardment.