triatic stay, trough of the sea
verso Plate I and portion of margin across gutter, facing (and showing some variety of offset from) Plate II (Signal Flags and Lights, Repeaters, etc),
90º cw, inv., 10-1.00-255
ex General Signal Book of the Navy of the United States of America (1876)
Phillips Library, PEM copy/scan : link
note :
The plates are identified as originating from the “Bureau of Navigation, 1883;” they were evidently added later to this book, hence the rough glueing / dramatic sea-land-sky scapes).
9649 Triangle, s.
9650 Triangular, ly.
9651 Triangulation.
9652 Triangulate, d, ing.
9653 Triatic stay.
9696 Trough of the sea.
link