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Concentration of Ores.
Patent for improvements to recovering ore using flotation methods.
Date:
December 17, 1918
Creator:
Wiser, Oba
System:
The Portal to Texas History
Screw-Driver
Patent for a screwdriver. Illustrations included.
Date:
December 29, 1908
Creator:
Winfrey, Edgar M. & Lilins, Thomas W.
System:
The Portal to Texas History
Calculator
Patent for a calculator which consists of semicircular device with movable pointers and number indexes printed on it that allows the pointers to be moved to different numbers to produce the answer to a math problem such as calculating the cost of goods sold by the pound in a store.
Date:
December 21, 1909
Creator:
Goss, George Wilson
System:
The Portal to Texas History