Examination of various Ores. 531 
frequently repeated, and with great care, fome fmall por- 
tion of the gold fail remains ; fo that the fmali quantity 
left in this cafe might eafily have either efcaped the 
mercury, or, have been left unobferved in the powder 
combined with fmall particles of it. 
We may therefore conclude, that in this ore the gold 
was in its native form, and not mineralized. 
exp. hi. We examined gold pyrites mixed with 
quartz, with a deep magnifier, and found evidently na- 
tive gold interfperfed. One hundred grains of this ore, 
was powdered; and boiled in nitrous acid diluted with 
water: a folution of iron took place, as in the firft 
experiment. The refiduum being expofed to a red 
heat, there was no appearance of fulphur; the gold 
was found in fuch large particles, and fo fimilar to na- 
tive gold, that we did not think it worth while to apply 
mercury. 
The gold being diflblved out by aqua regia , a quantity 
of quartz and arfenical fait was left. 
exp. iv. When gold and filver are found in their me- 
tallic form, it is not uncommon to find them mixed; but 
it feldom occurs, that they are mixed in fo large propor- 
tion as in an ore obtained from Norway, and which was 
\ 
given to Dr. hunter, by Mr. fabricius. 
The 
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