^{page 387 note 1} Although Hayford's theory is the nearest approach to truth that has yet been made, it does not afford a complete explanation of every observed anomaly. In my paper on the origin of the Himalayas I corrected all geodetic results in accordance with the Hayfordian system, and I then regarded the uneliminated residuals as indications of actual departures from isostasy. Mr. Fisher calls attention to a change in the observed value of g at Dehra Dun that has taken place between 1870 and 1904. This change is, however, apparent only; it is due to the recent introduction of a correction for the vibration of the brick pillar upon which the pendulum is swung.