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Officers for 1931
I34
CURRENT TOPICS.
[]. F. I.
For the magnetic phenomena taking place inside of an atom .oI is a very long time. Hence this brief interval is adequate for studies of the Zeeman effect, of the change of resistance in magnetic fields, of magnetic susceptibility and of change of dimensions (magnetostriction), when substances are placed in the strong though momentary field. The intensity of the brief field may be roughly judged by this. If a Dewar flask containing an upright glass rod 3 ram. in diameter surrounded by liquid air have the intense field applied to it, the rod is thrown up to a height of 7 or 8 meters, because the iiquid oxygen, being strongly paramagnetic, is drawn down into the flask, thus ejecting the rod. "If the Dewar flask is filled with liquid oxygen only, the force of attraction due to a field of 300,000 gauss produces a pressure of several atmospheres and the Dewar flask breaks." Usually the change of resistance caused by applying a magnetic field to a metal is a small fraction of one per cent., but with Kapitza's electromagnet 20 to 30 per cent. is not uncommon and in some cases the resistance of bismuth increases 2,000 times. G. F. S.
THE FRANKLIN INSTITUTE OFFICERS FoR 1931 President Vice-presidents Secretary Assistant Secrelary and Librarian Treasurer Assistant Treasurer Controller
NATHAN HAYWARD HENRY HOWSON C, C. TUTWILER WALTON FORSTALL W . CHATTIN WETHERILL HOWARD MCCLENAHAN ALFRED RIGLING BENJAMIN FRANKLIN MARSHALL S. MORGAN WILLIAM F. JACKSON, JR.
Board of Managers GEORGE H. BENZON, JR. EDWARD G. BUDD FRANCIS T . CHAMBERS G. H. CLAMER WALTON CLARK CYRUS H. K. CURTIS SAMUEL S. FELS A R T H U R W. GOODSPEED
CLARENCE A. HALL G E O R G E A. HOADLEY A. ATWATER KENT L. H. KINNARD ELISHA LEE ROBERT W . LESLEY LIONEL F. LEVY MALCOLM LLOYD, JR.
ROBERT M C L E A N CHARLES PENROSE JAMES S. ROGERS G E O R G E D. ROSENGARTEN E. H. SANBORN HASELTINE SMITH SXMUEL T. WAGNER
CURRENT TOPICS.
[]. F. I.
For the magnetic phenomena taking place inside of an atom .oI is a very long time. Hence this brief interval is adequate for studies of the Zeeman effect, of the change of resistance in magnetic fields, of magnetic susceptibility and of change of dimensions (magnetostriction), when substances are placed in the strong though momentary field. The intensity of the brief field may be roughly judged by this. If a Dewar flask containing an upright glass rod 3 ram. in diameter surrounded by liquid air have the intense field applied to it, the rod is thrown up to a height of 7 or 8 meters, because the iiquid oxygen, being strongly paramagnetic, is drawn down into the flask, thus ejecting the rod. "If the Dewar flask is filled with liquid oxygen only, the force of attraction due to a field of 300,000 gauss produces a pressure of several atmospheres and the Dewar flask breaks." Usually the change of resistance caused by applying a magnetic field to a metal is a small fraction of one per cent., but with Kapitza's electromagnet 20 to 30 per cent. is not uncommon and in some cases the resistance of bismuth increases 2,000 times. G. F. S.
THE FRANKLIN INSTITUTE OFFICERS FoR 1931 President Vice-presidents Secretary Assistant Secrelary and Librarian Treasurer Assistant Treasurer Controller
NATHAN HAYWARD HENRY HOWSON C, C. TUTWILER WALTON FORSTALL W . CHATTIN WETHERILL HOWARD MCCLENAHAN ALFRED RIGLING BENJAMIN FRANKLIN MARSHALL S. MORGAN WILLIAM F. JACKSON, JR.
Board of Managers GEORGE H. BENZON, JR. EDWARD G. BUDD FRANCIS T . CHAMBERS G. H. CLAMER WALTON CLARK CYRUS H. K. CURTIS SAMUEL S. FELS A R T H U R W. GOODSPEED
CLARENCE A. HALL G E O R G E A. HOADLEY A. ATWATER KENT L. H. KINNARD ELISHA LEE ROBERT W . LESLEY LIONEL F. LEVY MALCOLM LLOYD, JR.
ROBERT M C L E A N CHARLES PENROSE JAMES S. ROGERS G E O R G E D. ROSENGARTEN E. H. SANBORN HASELTINE SMITH SXMUEL T. WAGNER