Search for Fractional Charge on Tungsten Particles

The charge on some small tungsten particles was measured to test for the presence of fractional excess charges. In a sample of 3×${10}^{-10\mathrm{}}$ g, or ${10}^{12}$ atoms, of tungsten, no excess charges of $+\frac{1}{3}e$ or $-\frac{1}{3}e$ were found.