Carl. W. Mitman Curator of engineering at Smithsonian Institution with 1st cold electric light bulb, 9/6/24

C.W. Mitman of Smithsonian Institute with giant and midget bulbs, 3/12/25

First radio vacuum tube. Carl W. Mitman, Curator of Engineering, US Nat'l Museum, holding what is believed to be the 1st radio tube. It was made in 1898 by D. Mefarlan Moore of NY. Radio waves emanating from this tube ignited a bomb a city block away and blew up a miniature of the Battleship Maine (

Carl. W. Mitman, Curator of Smithsonian Institution with 3-wheeled auto, 9/6/24

Dr. D.C. Bardwell, of the Research Lab. of the U.S. Bureau of Mines, collecting gaseous radium emanation. The radium is in the little safe at the right. Collections are made at intervals of from 4 to 10 days. The gas is drawn off under vacuum and purified by a liquid air refrigeration. The purified

Carl W. Mitman, 6/18/24

Studying why fruits taste that way. E.K. Nelson of the Department of Agriculture is shown making tests with an apparatus which the Department imported from Germany for the purpose of studying the essential oils or "flavor-giving" content of fruits and vegetables. At present chemists are acquainted w

Dr. Nathan Augustus Cobb, technologist of the Dept. of Agric., who has discovered that by the use of a piece of glass he can invoke the aid of the sun in making microscopic studies of minute objects. Until this glass was used, the sun blurred instead of clarified the object

Measuring relative humidity by radio. Washington, D.C. June 9. The hair element for measuring relative humidity in radio weather sounding balloons has proved innacurate because of very slow response at the cold temperatures encountered in the upper atmosphere. F.W. Dunmore, Radio Engineer of Nationa