MEMORIAL TO ARTHUR LOUIS DAY1 (1869–1960)

Abstract

It is seldom given to one man to play a leading part in four different although distantly related scientific activities. Arthur L. Day left his signature on geophysical chemistry, volcanology, seismology, and ceramic research and industry. He came into science by way of research in pure physics. After graduating with the A.B. from the Sheffield Scientific School of Yale University in 1892, he was appointed Sloane Fellow in Physics, and earned the Ph.D. from Yale in 1894. He then devoted 3 further years to the activity that so many have found invaluable for consolidating one's knowledge of a subject: teaching its principles to others— in this instance to the Sheffield undergraduates. His teaching must have been effective, for in 2 successive years he won a place second only to the redoubtable William Lyon Phelps in the annual balloting by the undergraduates to select their most popular teacher. In the 1890's, advancement in the field of physics almost demanded a foreign, particularly German, postgraduate experience. Day spent the summer of 1893 at the World's Fair in Chicago, which (he said) ... brought together the greatest collection of electrical apparatus ever assembled in one spot up to that time, an inspiration to any student of physics with an instinct for research. Travels in the summers of 1894 and 1895 in Germany and Scandinavia were a further preparation for an unplanned excursion in 1897. On arrival in Germany Day went straight to the Physikalisch-Technische Reichsanstalt in Charlottenburg-Berlin, then one of the best-equipped physics laboratories in the world, and applied for a job as an unpaid assistant. Not only was he accepted, but presently he found himself on the regular staff as a result of the serious illness and total disability of his collaborator. Thus began a series of investigations on the high-temperature scale that occupied nearly 4 years in Germany and 10 in America. In the meantime, in Washington, F. W. Clarke, G. K. Gilbert, Waldemar Lindgren, and others associated with the U. S. Geological Survey and the departments of geology in the universities had become convinced that geologic science needed more chemistry and more physics, particularly of a quantitative kind. A beginning in quantitative geology had actually been made at the founding of the Survey in