View Original: | Sun valve designed by Gustaf Dalen, 1912, turns lighthouse on at night and off during the day, TM34299 - Tekniska museet - Stockholm, Sweden - DSC01443.JPG (3422x4721) | |||
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Keywords: Sun valve designed by Gustaf Dalen, 1912, turns lighthouse on at night and off during the day, TM34299 - Tekniska museet - Stockholm, Sweden - DSC01443.JPG en Exhibit in the Tekniska museet Stockholm Sweden This work is old enough so that it is in the public domain Photography was permitted in the museum without restriction 2014-09-16 own Daderot other versions cc-zero Collections of the Tekniska museet Uploaded with UploadWizard Gustaf Dalén Optical sensors |