Emery Rod

Emery Rod Construction Emery Rod construction is quite simple. Necessary components include four wooden rods, each l -inch square and 5 feet in length. Two rods are painted one side only with alternating bright colors (such as red and white), with each block painted in increments of tenths of feet, or in inches or centimeters, beginning at the top. The remaining two rods are connected to the painted rods (with bolts and \wing nuts) to form a parallelogram (Figure B, p. 2). NOTE: To prevent the rods from sinking into the sand and thus giving inaccurate elevation readings, it is recommended that 'foot pads,' made of small discs of wood or large bottle caps, be attached to the bottom of the two vertical rods .

from Woods Hole Institute Bulliten

http://web.whoi.edu/seagrant/wp-content/uploads/sites/24/2015/01/WHOI-G-01-001-Sea-Grant-Beach-and-Dune-Pr.pdf