Greer Garson

Marie Curie

Walter Pidgeon

Pierre Curie

Henry Travers

Eugene Curie

Albert Bassermann

Professor Je...

Robert Walker

David Le Gros

C. Aubrey Smith

Lord Kelvin

May Whitty

Madame Eugen...

Victor Francen

President of...

Elsa Bassermann

Madame Perot

Reginald Owen

Dr. Becquerel

Van Johnson

Reporter

Margaret O'Brien

Irene Curie ...

James Hilton

Narration Sp...

Mariska Aldrich

Tall Woman (...

Tony Carson

Man at Accid...

Ruth Cherrington

Swedish Quee...

Ray Collins

Lecturer (vo...

Guy D'Ennery

Professor (u...

George Davis

Cart Driver ...

Harold De Becker

Professor (u...

Franz Dorfler

Assistant Ta...

Justine Duney

Woman at Acc...

Tay Dunn

Man at Accid...

William Edmunds

Cart Driver ...

Nestor Eristoff

Board Member...

Al Ferguson

Man at Accid...

Edward Fielding

Board Member...

Howard Freeman

Prof. Consta...

Linda Lee Gates

Perot Grandd...

Marie Louise Gates

Perot Grandd...

Lisa Golm

Lucille (unc...

Ilka Grüning

Seamstress (...

Lumsden Hare

Professor Ro...

Teddy Infuhr

Son (uncredited)

James Kirkwood

Board Member...

Isabel La Mal

Woman at Acc...

Gene Lockhart

Bit Part (un...

Miles Mander

Businessman ...

George Meader

Singing Prof...

Dickie Meyers

Master Micha...

Noel Mills

Wedding Gues...

Leo Mostovoy

Photographer...

Alan Napier

Dr. Bladh (u...

Moroni Olsen

President of...

María Pagés

Woman at Acc...

Gigi Perreau

Eve at 18 Mo...

Francis Pierlot

Monsieur Mic...

Nita Pike

Woman at Acc...

Dorothy Raye

Nurse (uncredited)

Almira Sessions

Madame Micha...

Arthur Shields

Businessman ...

Wyndham Standing

King Oscar (...

Ray Teal

Driver (uncr...

Charles Trowbridge

Board Member...

Michael Visaroff

Proud Papa (...

Marek Windheim

Jewelry Sale...

Frederick Worlock

Businessman ...

Eustace Wyatt

Doctor (uncr...