President Roosevelt was not impressed with a memo informing him that 'Such preparations shall be made as will completely obscure all Federal and non-Federal buildings occupied by the Federal Government during an air raid for any period of time from visibility by reason of internal or external illumination. Such obscuration may be obtained either by black-out construction or by termination of the illumination.'

'Tell them,' Roosevelt told the writer, 'that in buildings where they have to keep the work going to put something over the windows; and, in buildings where they can let the work stop for a while, turn out the lights.'