American Scientists

First Day of Issue
June 16, 2011  •  St. Paul, MN 55164
For Sale in Post Offices…or by calling 1 800-782-6724 to place an order with someone in customer service.

The third American Scientists issuance honors chemist Melvin Calvin, botanist Asa Gray, physicist Maria Goeppert Mayer, and biochemist Severo Ochoa.

For each stamp in this block of four, art director Ethel Kessler collaborated with Greg Berger of Bethesda, Maryland, to create a collage featuring a photograph and signature of the scientist, along with items such as equations and diagrams that are associated with the scientist’s research.

Melvin Calvin

The stamp art collage utilizes the following design elements: a 1948 photograph of Calvin in a laboratory at the University of California at Berkeley; a 1970 photograph of Calvin by Yousuf Karsh; Calvin’s signature, from a 1961 letter to a colleague; excerpts from equations of the carbon cycle (also known as the Calvin cycle) that Calvin published in a 1962 article in Science magazine and in his 1992 autobiography; chemical symbols and structures he used to represent the conversion of carbon dioxide and water into organic compounds during photosynthesis.

Asa Gray

The stamp art collage utilizes the following design elements: a photograph of Gray in his prime, circa 1860s; illustrations of plants studied by Gray (Shortia galacifolia and Aesculus discolor); Gray’s signature, from an 1855 letter to naturalist Spencer F. Baird; the words “Shortia galacifolia” in Gray’s handwriting; and his printed abbreviation of the title of his work Synoptical Flora of North America.

Maria Goeppert Mayer

The stamp art collage utilizes the following design elements: photographs of Mayer, circa 1940s; Mayer’s autograph, in a book by British physicist James Jeans that she used in her teaching; part of a chart of the elements and isotopes with “magic numbers,” from an article Mayer published in Scientific American in 1951; and a schematic diagram of nuclear shell levels, from Mayer and Jensen’s Elementary Theory of Nuclear Shell Structure.

Severo Ochoa

The stamp art collage utilizes the following design elements: photographs of Ochoa in his laboratory in 1959; Ochoa’s signature, from a 1949 letter to colleague Arthur Kornberg; a scheme, from one of his publications, representing the replication of viral RNA; and an equation representing the bacterial ribosome cycle in polypeptide synthesis.

The American Scientists stamps are being issued as Forever® stamps. Forever stamps are always equal in value to the current First-Class Mail one-ounce rate.

Digital Color Postmarks

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