BY A. M. WEINBERG

HERBERT G. "MAC" MACPHERSON died suddenly in Guadalajara, Mexico, on January 26, 1993, at the age of eighty-one. Thus passed one of the most highly respected pioneers of nuclear energy.

MacPherson's scientific career began at the University of California, Berkeley, where he received the bachelor's degree in 1932 and the Ph.D. degree in physics in 1937. While at Berkeley he was much influenced by Professors R. B. Brode and Leonard Loeb. His first scientific paper (1934), of which he was the sole author, described a definitive experimental refutation of the so-called F. Allison magneto-optical method of chemical analysis. In this first paper MacPherson already displayed qualities of scientific common sense and impeccable responsibility that were the hallmarks of his entire career, both as a physicist and as an engineer. During this early period MacPherson worked on cosmic rays with Brode and M. A. Starr, and during a short stay at the Weather Bureau, he analyzed the accuracy of the Smithsonian Institution's measurements of the solar constant.

In 1937 when MacPherson joined the National Carbon Division of the Carbide and Carbon Chemicals Company, physicists in industrial companies were rare; indeed MacPherson was the first physicist hired by National Carbon. His first job was to investigate by sophisticated spectrophotometric methods, the