PROF. D. B. MCQUISTAN, who recently retired from the Freeland chair of natural philosophy in the Royal Technical College, Glasgow, has now, through failing health, been forced to relinquish a lifetime devoted to the cause of education. A brilliant student of the University of Glasgow, he was awarded the Thomas Logan Memorial Medal and Prize for the most distinguished graduate in arts of his year, with first-class honours in mathematics and natural philosophy, and in classics. The William Houlds-worth research studentship afforded him the opportunity of spending a profitable year at the University of Cambridge, and, along with his later services as a mathematical teacher, he was well equipped for the duties of the chair which he afterwards occupied with great distinction. Many thousands of students will remember with gratitude his lucidity as a lecturer, and his exceptional aptitude in clarifying any difficult mathematical or scientific complexity. His popular lectures of scientific interest to varied audiences were an inspiration to the expert and a delight to the novice.