. The literary digest. ces closelyresembled those obtained from sections of many metallic meteo-rites, except in the form of the crystals. Some of the nuggetsalso showed cavities and enclosures of quartz, ferric hydroxid,and argillaceous matter, altho in many cases none was visible onthe rolled surface of the nugget, the non-appearance of the im-purities on the surface being due to the soft gold having beenusually beaten down, by rolling and attrition, in such a way asto cover over and hide the enclosures or render them less con-spicuous. It was found also that many nuggets when heated strongl
. The literary digest. ces closelyresembled those obtained from sections of many metallic meteo-rites, except in the form of the crystals. Some of the nuggetsalso showed cavities and enclosures of quartz, ferric hydroxid,and argillaceous matter, altho in many cases none was visible onthe rolled surface of the nugget, the non-appearance of the im-purities on the surface being due to the soft gold having beenusually beaten down, by rolling and attrition, in such a way asto cover over and hide the enclosures or render them less con-spicuous. It was found also that many nuggets when heated stronglyin a Bunsen burner became blistered, and that these blisters burst Vol. XVI., No. 10] THE LITERARY DIGEST. 287 with a sharp report sometimes accompanied by the projection ofsmall pieces of gold; they also gave off gases or vapors, whichissued under considerable pressure and forced out the Bunsenflame into little blowpipe-like jets. It was thought that thesephenomena might be due to the presence of enclosed gases under. ETCHED SECTION OF SAME NUGGET, SHOWING CRYSTALS. pressure, but when the nuggets showing these blisters or blebswere immersed in a solvent and the walls of the blebs slowlydissolved away, there was no escape of gas. Subsequent investigations showed that the nuggets yieldedbut very small quantities of permanent gas, when examined at ahigh temperature in vacuo for occluded gases, and it was foundthat the vapor given off was mainly that of water mixed withsome sulfur dioxid and air. The water vapor was probably de-rived from the hydious oxid of iron and argillaceous matter en-closed in the nuggets, and the sulfur dioxid from pyrites or othersulfur-containing minerals Attempts were made to prepare artificial nuggets by electro-lytic deposition ; around wires, fairly thick masses were obtained,the sections of these showing well-defined rings and traces of crys-talline structure.; the rings or successive coats were clearly due tochanges in the strength of the current a
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