PERHAPS you will allow me to make known through your columns to those who have from time to time made inquiries concerning my Absolute Sine Electrometer, that, after many months' work, I have satisfactorily concluded a series of experiments with the instrument which was made for Prof. Anthony. When this instrument was finished last year, I made some observations with it which were so unsatisfactory that I did not feel justified in allowing it to be sent to America. I have now, however, removed all the difficulties connected with it, and I uniformly obtain results perfectly consistent one with another. Indeed my difficulties during the last six weeks were due to the fact of my employing cells which were not sufficiently constant, and not to any fault of the electrometer, a fact which I did not realise for some time.