Professor W.C. Röntgen Discovers X-Rays

The model department of the United States Patent Office in Washington is illuminated here and there with the original models of the very great...

Chester Carlson Invents Machine To Copy Documents

The model department of the United States Patent Office in Washington is illuminated here and there with the original models of the very great...

Charles Babbage Invents Mechanical Calculator

The model department of the United States Patent Office in Washington is illuminated here and there with the original models of the very great...

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