NOTES ON TIIE REFRACTIVITIES OF THE INACTIVE GASES.
Ilere, too, it wil 1 be noticed tliat the quotiënt of the tirst and third element of eacli series is a liigher number tlian tliat furnislied bv the otlier three eleinents; and tliis alfords a strong proof of the periodicity
7.0 G.0 5.0
0 20 40 60 80 100 120 110 Atomatic Weights.
of all three series of elements. The analogy is also seen in the accompanying diagram, where ordinates are atomic weights, and abcissae, refractivities compared witli air as unity.