With a copper wire and galvanised nail, the measured voltage is 0.93V, comfortably within the measurement range of the XO1 laptop. The laptop produced negligible loading on the open circuit voltage. With copper wire and an ungalvanised nail the voltage was 0.49V. | With a copper wire and galvanised nail, the measured voltage is 0.93V, comfortably within the measurement range of the XO1 laptop. The laptop produced negligible loading on the open circuit voltage. With copper wire and an ungalvanised nail the voltage was 0.49V. |