Now, with regard to this substance, let me tell you briefly how we get it. The process used to be this. The ore which I shewed you just now was taken, and digested in nitro-muriatic acid of a certain strength, and partly converted into a solution, with the leaving behind of certain bodies that I have upon the table. The platinum being dissolved with care in acids, to the solution the muriate of ammonia was added, as I am about to add it here. A yellow precipitate was then thrown down, as you perceive is the case now; and this, carefully washed and cleansed, gave us that body [pointing to a specimen of the chloride of platinum and ammonium], the other elements, or nearly all, being ejected. This substance being heated, gave us what we call platinum sponge, or platinum in the metallic state, so finely divided as to form a kind of heavy mass or sponge, which, at the time that Dr. Wollaston first sent it forth, was not fusible for the market or in the manufacturers’ workshops, inasmuch as the temperature required was so high, and there were no furnaces that could bring the mass into a globule, and cause the parts to adhere together. Most of our metals that we obtain from nature, and work in our shops, are brought at last into a mass by fusion. I am not aware that there is in the arts or sciences any other than iron which is not so. Soft iron we do not bring together by fusion, but by a process which is analogous to the one that was followed in the case of platinum, namely, welding; for these divided grains of spongy platinum having been well washed and sunk in water for the purpose of excluding air, and pressed together, and heated, and hammered, and pressed again, until they come into a pretty close, dense, compact mass, did so cohere, that when the mass was put into the furnace of charcoal, and raised to a high temperature, the particles, at first infinitely divided—for they were chemically divided—adhered the one to the other, each to all the rest, until they made that kind of substance which you see here, which will bear rolling and expansion of every kind. No other process than that has hitherto been adopted for the purpose of obtaining this substance from the particles by solution, precipitation, ignition, and welding. It certainly is a very fine thing to see that we may so fully depend upon the properties of the various substances we have to deal with; that we can, by carrying out our processes, obtain a material like this, allowing of division and extension under a rolling mill—a material of the finest possible kind, the parts being held together, not with interstices, not with porosity, but so continuous that no fluids can pass between them; and, as Dr. Wollaston beautifully shewed, a globule of platinum fused by the voltaic battery and the oxyhydrogen blowpipe, when drawn into a wire, was not sounder or stronger than this wire made by the curious coalescence of the particles by the sticking power that they had at high temperatures.