DR. HERBERT CHATLEY prepared a paper on 'terminal velocities' for delivery to the Junior Institution of Engineers on October 13. It is now published in the December issue of the Journal of the Institution. In many engineering and physical problems of the present day, the question often arises as to the maximum velocity developed when a body falls in a fluid medium. To give a rough idea of the terminal velocities, Dr. Chatley compares the impact velocity of a stream-lined aerial bomb and the speed with which the finest clay suspensions settle in water. Between these speeds he considers the landing speed of parachutes, the fall of rain or oil-drops, the vertical current speeds necessary in coal dust or grain elevators, the suspension of sand or silt in rivers, and the settlement of dust particles in a room.