The London, Edinburgh and Dublin philosophical magazine and journal of science . their investigations on thespectra of the elements, that within a group of chemicallyrelated elements the distance apart of the lines of a pairincreases regularly with the atomic weight. They state thatiu the case of alkali metals the atomic weight is very nearlyproportional to the square root of this distance. We wish todraw attention to the fact that for the other groups in whichline-pairs have been observed, the relation between the widthof the line-pairs and the atomic weight is capable of beingexpressed by a
The London, Edinburgh and Dublin philosophical magazine and journal of science . their investigations on thespectra of the elements, that within a group of chemicallyrelated elements the distance apart of the lines of a pairincreases regularly with the atomic weight. They state thatiu the case of alkali metals the atomic weight is very nearlyproportional to the square root of this distance. We wish todraw attention to the fact that for the other groups in whichline-pairs have been observed, the relation between the widthof the line-pairs and the atomic weight is capable of beingexpressed by a simple formula :— In each group of chemically related elements the atomicweight varies as some power of the distance apart of the twolines of a pair. of Radium in the Periodic System. An The exponent is a proper fraction. This result may other-wise be expressed thus :— The logarithms of the atomic weights and those of the dis-tances ivhen plotted as coordinates lie on a straight line for achemically related group of elements. The following two figures illustrate this +.6 Logarithm of the line-distance (01 scale-division=2*3 per cent, of the value). In fig. 1 it will be seen that among the alkalies potassiumalone falls slightly below the line passing through the re-maining points. We do not mean thereby to suggest thatthe directly determined atomic weight of potassium is in-correct ; but it appears to us interesting that the straight-linelaw is appreciably departed from precisely in the case of theelement whose atomic weight in the periodic system pointsto an unknown disturbing cause, which produces the inversionof the positions of argon and potassium. As regards boron, gallium, and indium, the radiation ofthese elements in a magnetic field has not been the other hand, there is no room for doubt as regards theline-pairs corresponding to aluminium and thallium. Thesame applies to the alkali group, where only the two yellowsodium lines have been investiga
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Keywords: ., bookcentury1800, bookdecade1840, bookidlondon, booksubjectscience
