Dr. Hogg is distinguished for his contributions to atmospheric electricity, cosmic rays and photoelectric photometry, the connecting feature being the accurate measurement of small currents. He displays great skill in design and manipulation of equipment and great care in observing technique. Outstanding publications are his description of intermediate ions in the atmosphere, his substantial memoir on cosmic rays and his recent photoelectric work. With amplifiers of his own design he has produced light curves of variable stars which have not been surpassed and fundamental measures of monochromatic stellar magnitudes which are the most accurate and significant produced anywhere. He has recently determined the magnitude of the Large Magellanic Cloud, finding a value very different from those previously given, and in a review of published earth current observations found a new parameter of great importance.