Abstract
A transportable standard current source has been made with a mercury battery as a voltage reference combining with a reference resistor. The stability is better than 0.2ppm/day. It is confirmed that this current source can be used to transfer a standard current with the accuracy within 1ppm from a labolatory to other one. In connection with this experiment, the annual change and temperature coefficient of the electro-motive force of a mercury battery have been measured pricisely.
