LXI. The laws of deflexion of a particles through large angles

But whatever value is attached to the numerical evidence by those competent to judge, the broad conclusion from the direction of the changes is unaffected.I should llke also to reply to one criticism which has been made.It is not necessary to the hypothesis that the atomic free frequency should be absolutely invariable throughout all chemical changes.If it were the case that a slight change (say 1 per cent.) in the atomic free frequency would account for all the observed changes of refractivity and dispersion, the criticism would have force.But any one who examines the figures in lhe table for (e. g.) hydrogen, nitrogen, and ammonia, will see that no slight change in a frequency can possibly account for the observed changes.For hydrogen no2X 10-~r=12409, for nitrogen 17095.For ammonia the nmnber which expresses its average value is 8135, an enormous drop.At the same time the refractivity has gone up only 3} per cent.But if the number of vibrators had remained constant while the average free frequency decreased, the increase of the refractivity must have been much greater than this.Hence, to account for the observed changes, one must also assume that the number of vibrators (? electrons) has fallen off in about the same proportion as the frequency.These two hypotheses seem much more improbable than that which is here put forward.