[Read before the Wellington Philosophical Society, 21st February, 1880.]

Upon the authority of Fisher it is now supposed that argentic-oxide is not decomposed by mercury; but I find that, when these two substances are kept for some weeks in contact, whether in light or not, a considerable quantity of silver amalgamates with the mercury, and a crust of yellow mercuro-oxide is formed, demonstrating that this silver compound is divested of its oxygen by mercury, but at a very slow rate of speed. The same decomposition takes place if the two substances are kept immersed in caustic potash.