An investigation of an electromagnetic method for the measurement of body composition.

This note presents an investigation of an electromagnetic method for the measurement of the volume of electrolytes in the human body. The shift in the frequency of a resonant transmission line, wound as a large helix, when a phantom containing 1% saline was inserted coaxially, was found to be proportional to the volume of saline for small volumes only and for larger volumes became proportional to the surface area. This was observed for twophantom geometries. The volume of saline used ranged from 10 ml to 60 l. These observations suggest that the resonant electromagnetic system only responds to water at the surface.