That's Dr. Robert Goddard, and the image came from NASA's GRIN (Great Images In Nasa) site, an amazing resource for historical photos about aerospace and space.
Each image is available for downloading in several sizes and resolutions, and also have additional information about the photos.
From the site description of this photo:
Dr. Robert H. Goddard at a blackboard at Clark University in Worcester, Massachusetts, in 1924. Goddard began teaching physics in 1914 at Clark and in 1923 was named the Director of the Physical Laboratory. In 1920 the Smithsonian Institution published his seminal paper A Method for Reaching Extreme Altitudes where he asserted that rockets could be used to send payloads to the Moon. Declaring the absurdity of rockets ever reaching the Moon, the press mocked Goddard and his paper, calling him "Moon Man." To avoid further scrutiny Goddard eventually moved to New Mexico where he could conduct his research in private. Dr. Goddard, died in 1945, but was probably as responsible for the dawning of the Space Age as the Wrights were for the beginning of the Air Age. Yet his work attracted little serious attention during his lifetime. However, when the United States began to prepare for the conquest of space in the 1950's, American rocket scientists began to recognize the debt owed to the New England professor. They discovered that it was virtually impossible to construct a rocket or launch a satellite without acknowledging the work of Dr. Goddard.
Check it out, tons of history and pictures.
Posted by Ted at March 29, 2006 11:59 PM