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itself. The texture, brittleness, and cavity in the lumpshewing that the platina, though it had approached con-siderably towards fusion, had not melted perfectly, the au-thor proposes to repeat the operation with a degree of firestill stronger.

It must be observed on this experiment, that in the pre-cipitate made use of, the platina cannot be supposed to havebeen pure from other metals. Solutions of platina plainlycontain iron, as appears from their striking a blue colourwith the Prussian alcali : either fixt or volatile alcaliesprecipitate this iron along with the platina; and as partof the platina remains dissolved, the precipitate may con-tain a greater proportion of iron than the grains of platinaitself did. Though the iron is in a state of calx, dissolubleby the glass, and not miscible with metallic bodies in theirperfect state; yet a slight introduction of inflammablematter is sufficient to revive it, calces of iron seeming tobe easier of revival than those of any other metal. Theblack colour of the glass was owing doubtless to the iron;nor would it be surprising, if preparations of platina shouldon further trials be found to tinge glass of all the coloursthat iron can communicate. If the platina really melted,the fusion may be ascribed to a mixture of the same metal:but most probably the appearance of fusion was no other,than a conglutination of the impalpable atoms into whichthe platina had been divided, similar to what we find tohappen when the crude mineral is urged with a strong sire.

From the experiments related in this section it appears,that platina is not onlv of itself refractory in the fire; butobstinately resists the additions, and managements, bywhich every other known metallic body is corroded, dis-solved, or changed to a vitreous state. If, as the chemiststeach, metals are the more perfect, in proportion as theyare the more permanent and the less susceptible of changes,platina is of all known metals the most perfect.