"The enclosed letter, marked No. 1, is written on paper treated by our process. Would you be able to have a thorough examination made of it, and to let us know the results?"
Linus Pauling. Letter to Warren C. Lothrop. November 1, 1944.

"It would seem that [the study of invisible ink] had never been treated very seriously during the hundreds of years prior to the first World War. During that war, enormous advances were made, and the supposition is that both Britain and Germany continued actively and aggressively in the field after the war."
Warren C. Lothrop. "The Licence of Ink."  5, ca. .

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