This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
Chinese Naval Mine. Ming Dynasty Chinese illustration of naval mine from the th century military treatise of the Huolongjing compiled by Jiao Yu and Liu Ji with Jiao's preface added in This particular sea mine was called the 'submarine dragon king' shui di long wang pao The firing mechanism consists of floated incensestick which