United States. Patent Office · Washington, D.C., Govt. Print. Off. · leaf 987
Patented Nov. 2,1915. 2.SHEETS-SHEET 2. … INVENTOR. BY ^^ ATJQRNEY COLUMBIA PLANOORAIH CO.. WASH1N0TON, D. C. UNITED STATES PATENT OFFICE. CHARLES M. HECK, OF RALEIGH, NORTH CAROLINA.METHOD OF COMPARING SOUNDS. 1,159,023. Specification of Letters Patent. Patented Nov. 2,1915. Original application filed February 5, 1915, Serial No. 6,316.…
Phonograph · Patents
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