A simple heliograph is easily constructed, and uses the sun's rays to transmit messages, in morse code, over distances up to 100 kilometres.

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Details

Creative#:

TOP23720311

Source:

達志影像

Authorization Type:

RM

Release Information:

須由TPG 完整授權

Model Release:

No

Property Release:

No

Right to Privacy:

No

Same folder images:

Same folder images