Gold is not acted on by any of the acids alone. When exposed to the mixture of nitric with hydrochloric acid (in the proportion of one part nitric to four of hydrochloric) called _aqua regia_, it dissolves without residue, the solution giving a purple precipitate with protochloride of tin, and a brown precipitate with protosulphate of iron. Electrum, the mixture of silver with gold above alluded to, is only partially soluble in aqua regia, giving a residue of chloride of silver. The solution is acted on by protosulphate of iron, as already explained. The following simple mode of detecting attempts at imposition in gold dust is worthy of being recorded in this place. Place a little gold dust in a glass tube or earthenware saucer, and pour nitric acid upon it; then hold the glass or saucer over a flame, or upon a few embers, until red flames (nitric vapors) arise; if it be pure gold, the liquid will not become discolored; but if pyrites or brass-filings should have been mixed with it, the acid will become turbid, green, and black, discharging bubbles of gas. After the ebullition has ceased, the residue should be washed with water, and acid again poured upon it, when the same effect may be observed, but in a less degree; and if the experiment be repeated till all effervescence ceases, it will finally leave the gold dust pure. FOOTNOTES: [17] Mohs' Mineralogy, by Haidinger, vol. ii. p. 438. [18] A _very rough_ estimate of the value of specimens of native gold may be obtained by multiplying the specific gravity by 4; the result gives the value in shillings nearly. [19] Abridged from Dufresnoy's "Mineralogie." CHAPTER XIV. ADDITIONAL RECENT EVENTS. The history of the laws of a State affords the best idea of its social condition--present and prospective; for they are framed from the necessity of circumstances and the demands of the inhabitants. We may, therefore, see the condition and the progress of the Californians in their legislative transactions. The California Legislature adjourned on the 22d April. They have passed a law creating a State assayer, until a mint be established in California. Among the one hundred and forty-three acts and joint resolutions passed, we notice the following: