[ 5oi ]

quart of distilled water, the filtered liquor was of a darkreddish colour : the remainder, boiled in frelh quantitiesof water, gave an olive-green tincture. The boiling beingrepeated, and the matter rubbed in a mortar, till it gaveno more tinge to the water, the part which remained atlast undissolved was a dark-coloured powder, which hadnothing of the appearance of platina, but was found to beno other than platina divided. This platina was treated inthe fame manner with frelh hepar, three or four times :the crucibles always failed and were much corroded, andthe platina was reduced into a powder so subtile, that itcould not be separated by washing from the parts of thecrucibles which were pounded with it.

I tried also a hepar made in Stahls manner, by meltingvitriolated tartar with powdered charcoal. This mixturemelted very easily, without any addition of the alcalinesalt or common salt,which are generally thought necessaryfor promoting the fusion : for though vitriolated tartar isvery hard of fusion by itself, yet here, its vitriolic aciduniting with the inflammable part of the charcoal intosulphur, the matter becomes a compound of sulphur andalcali, and melts as easily as the hepar made directly fromthose ingredients. Platina, treated with this hepar, sufferedthe lame change as from the other. The crucibles wereequally corroded : the watery solutions of the mass werepartly reddish, and partly of an olive-green colour: thegrains of platina, previously agglutinated into a lump bystrong sire, were disunited, and in great part divided into apowdery form.

It appears therefore that platina is divided by hepar sul-phuris in fusion, nearly in the same manner as by long ce-mentation with nitre : it remains to examine whether anypart of it was truly dissolved, so as to be taken up by thewater along with the sulphureous alcaline mixture. I sil-

T 11 2 tered