Jennifer, Perhaps the SpG should be stated as: mass of object / mass
of displaced water. Density can be expressed in different units like
Gm/CC or Oz/CuIn but SpG is always relative to the density of water.
So the in the metric system, the numbers are the same ie the density
of water is 1 Gm/CC or (8Lb/Gal etc) and the SpG is 1 (the units
cancel out). – Looking forward: Alan Shinn