U.S. Patent Act
..Part II. Patentabililty of Inventions and Grant of Patents
....Chapt. 11. Application for Patent
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The Commissioner may require the applicant to furnish a model of convenient size to exhibit advantageously the several parts of his invention.
When the invention relates to a composition of matter, the Commissioner may require the applicant to furnish specimens or ingredients for the purpose of inspection or experiment.
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