Materials & Manufacturing
Glass, steel, paper, and the processes that turn raw material into everyday objects.
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Who put a grid in the endpapers of a 1624 book about ciphers?
A blank leaf in a book of secret writing has squares hiding in it. Change the light and see if you can tell who put them there.
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What can you read on a blank sheet of paper?
Before a Philadelphia printer could turn a sheet into money, a Pennsylvania mill had already put two clues into it. One was blue. The other caught the light.
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What did the lines in Jefferson’s paper give away?
A scrap from an early draft of the Declaration had lost the part of the sheet that might have named its maker. A conservator still had two sets of lines to go on.
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Can a watermark date an undated list of lead prices?
Sir G. W. Denys left a list of prices. A papermaker left a year. Which one belongs at the top of the page?