In preparing a specimen of diamond boron by Wöhler and Deville's method, the idea struck us of substituting silver, gold, or some other metal in place of the aluminium. We thought that by so doing we might be able to save considerable expense if the silver would dissolve the boron; because in the case of aluminium the byproducts are useless, whereas in the case of silver the byproducts are easily reconverted into metallic silver. On making an experiment with silver in place of aluminium, we found that it did dissolve boron, and that on dissolving the silver away with nitric acid a slate-grey powder was left behind. This powder, on being examined after purification, was found to be boron, and to contain nothing but boron; under the microscope, it presented a complex composition, some being transparent and some opaque,—the opaque portion consisting of hexagonal prisms exactly like those of graphite; the transparent portion being composed of plates and a few small tetrahedra. The quantity obtained was but small, so we repeated our experiment several times, at last obtaining sufficient to examine the properties of these crystals.