The text and illustrations of US patents published before March 1, 1989 are in the public domain unless the patent text contains a specific notice that portions are copyrighted. See 37 CFR 1.71(d), 37 CFR 1.84(s)
The original patent contains no such notice, so its contents are in the public domain.
Note: This only applies to images published before March 1, 1989. Patents published after that date are most likely copyrighted, unless in the public domain for another reason, such as {{PD-ineligible}}.
Captions
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Items portrayed in this file
depicts
layer
quantity: 5
made from material: emulsion
made from material: dye
inception
5 April 1938
media type
image/png
checksum
d6d225e11bf102d80f6323361d2d0fff96ac1f41
determination method or standard: SHA-1
data size
155,102 byte
height
518 pixel
width
1,382 pixel
instance of
line art
has use: diagram
diagram
has characteristic: line art
File history
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