A new concept, namely, the original natural water formed from Zn2+ etc.-saturated water vapor, is presented according to the experimental fact that the limiting transfer concentration of trace-metal ion cycle with water evaporation equals the ion baseline of natural water. A new concept, namely, the original natural water formed from Zn2 + etc.-saturated water vapor, is presented according to the experimental fact that the limiting transfer concentration of trace-metal ion cycle with water evaporation equals the ion baseline of natural water.