GOLD. 



anJ w'ii:-rc this takes place, griipft, or nells, arc found whicli 

 contain the greateft proportion ot' gold. The proprietor of 

 tliefe mines extradled out of fiich nells, in no more than 

 twenty-two days, 189 marcs of pure gold, although a hundred 

 weight of the ore yields no more than from 10 to 12 

 grains of that metal. Formerly upwards of a thoufand 

 workmen were emploved in thefe gold-inine5 ; and the pro- 

 prietors ftill pofTefs 86 mills, by which from 10 to 12 pounds 

 (of 12 ounces) of mercury inprcgnatcd with gold are pro- 

 duced per day. Twelve pounds of mercury contain two 

 marcs of gold. There are likcwife feveral auriferous rivers 

 on the S. tide of the Apenainc Alps, between mount Rofa 

 and tlie valley of Aolla, fuch as the Avanlon, which runs 

 from the valley of Challant into the Doire, and where fome 

 gold-mines were alfo worked by the Romans ; the Oreo, &c. 



Sweden has a gold mine zX. Edelfors in Smoland : the gan- 

 gne, a brownilli quartz, is fuid to be in a kind of hornblende 

 flate, which alto con::\ins the metal diffeminated. 



Gold has alfo be.-n found in Great Britain : in Cornwall ; 

 at Lead-hills, in Scotland, diffeminated in quartz ; at Wick- 

 low, in Ireland, under th.e foil, and in a ilream which runs over 

 rocks of clay-flate with veins of quartz. It belongs to the 

 deep yellow variety. 



jlfia — The gold-ores of Siberia are partly of the light 

 coloured, but principally of the deep coloured variety : tfiat 

 of Berezof; which occurs in pyrites, or rather brown iron 

 ftone, and iron fnot quartz, and in the rock which ferves as 

 gangue to the red lead ore, belongs to the latter. Patrin 

 mentions a fpecimen of gold in Ipangles on hornfilvcr, found 

 in one of the filver mines of Schlansrenberjr. 



The geognollic relation of the gold found iu feveral parts 

 of India, in Japan, the Philippine and Maldive iflands, 

 Sumatra, Borneo, &c. is not known ; all the fpecimens from 

 India, that have come under our infpedtion, were ;n the form 

 of fmall rounded and amorphous particles in quartz, and be- 

 longed to the deep yellow variety. 



Africa. — Of the occurrence of gold in this part of the 

 world we know fo much, that the greatcil part, at leafl of 

 that which comes to Europe, is deep yellow and in grains. 

 African travellers have made us acquainted with a few of its 

 localities, but not with any particulars relating to its geognof- 

 tic habitudes. Though the commerce of gold-powder extends 

 almoft over the whole of Africa, yet, according to Heercn, 

 tJiere is none to be found in its northern parts. Among the 

 principal African gold mines are thofe of Kordofan, between 

 13arfur and Abyflinia, mentioned by Browne. The an- 

 cients, fays Brongniart, appear to have been acquainted with 

 thefe mines : they confidered Ethiopliia as a country rich in 

 gold ; and we hnd in Herodotus, that the king of that coun- 

 try exhibited to the ambaffadors of Cambyies all the pri- 

 foners of war fettered with chains of gold. 



A fecond moll confiderable dillritl for gathering gold- 

 powder appears to be fouthv.ard of the great deiart of Zahara, 

 in the well of Africa, at the foot of thofe lofty ridges of moun- 

 tains on which originate, among many inialler rivers, the Sene- 

 gal, the Ganibier,and Niger. The country of Bambouk, at the 

 i>I.E. of thefe mountains, is, according to Golberry, that 

 V. liich furnilhes the greatell quantity of gold wiiich is fold 

 on the well coall of Africa, from the mouth of the Senegal 

 to the Cape Palmas. This gold is fov-nd in fpanglcs and fiiiidl 

 lumps, principally near the iurface of the earth, in the beds of 

 rivulets, and iJways in a ferruginous foil. In fome parts of 

 the country the negroes link fomething like Ihifts, but v.'ith- 

 out giving any fupport to the fides of the pit ; nor are tiicy 

 wont to follow up the vein, if any Ihould appear, or to make 

 galleries. The metal is obtained by repeated walliing of l!«e 

 •arth that includes it. The fame country furnillies likewise 



the greatell part of the gold carried to Morocco, Fez, ard 

 Algiers, by the caravans which, from Tombuftoo, trav.-l 

 through the great defart of Zahara. The gold which is brought 

 to Cairo and Alexandria from Senaar comes likcwife frtm 

 thefe See Parke's travels, where alfo an interelling account 

 is to be found of the gold in Manding, and of the procefe by 

 which the negroes obtain it. 



The third principal dillria of Africa, for colleclin? eold 

 IS on theS.W. coall between ,5- and 22' S. lat. oppof.^ 

 Madagafcar. Phis gold comes principally from the country 

 ot Sofala. According to tlie relation of fome traveller?; iii 

 this part of the world, the gold is found there not only iti 

 powder, but likewife in veins. Some an: of opinion that 

 the country of Ophir, from whence Solomon obtained eoW 

 was lituated on this coall. ° ' 



ylnL-nca.—TK- gold of this part of the world, as far as 

 vve are acquamtcd with it, is fo equally the produaioa 

 of the fand of rivers and of alluvial land ; but it is alfo, thougli 

 rarely, found in veins. South America, particularly Bralll, 

 Clicco, and Chili, are the countries that yield moll ; but fomt- 

 IS alio found in North America, particularly in Mexico 

 where it occurs along with lllver-ores. The annual produce 

 01 thefe Mexican mines is valued at from 1 2 to 1 500 kilograms. 

 All the rivers of the Caraccas, 10"= north bt. are aurife- 

 rous. 



The gold of Chili, according to Frezier, is lodged in the 

 all'.'.vial formation. 



The Peruvian gold occurs in ferruginous quartz ; that ot 

 Choco, the richell province in gold in South America is 

 found as grains in alluvial country, and in rocks belonging o 

 the neweft fletz-trap formation. Almoll all we know refpict- 

 ing the geognollic lltuation of the gold of Spanilh America, 

 we owe to M. de Humboldt. 



Brafil furnirnes gold in abundance, and it is from thence 

 that the greatell part aclually feen in commerce is brou'^iit to 

 Europe. There are, however, properly fpeaking, no°gold- 

 mines in that country ; the gold is not found there in v; ins 

 but difTen-.inated in fand and other alluvial depofitions, out of 

 w 'uich it is obtained i:i the ufual manner. 



The gold that has been furnilhed by Brafil within 

 120 years, may be valued (according to Correa) at 

 2,406,000,000 of French Hires ; and, according to other 

 authors, the amount is calculated to be 24,000,000 per 

 annum. Brongniart. See Ohes- 



Ohfcrvations — i. It would appear that mod writers who 

 adopt Werner's diftinftion between gold-yellow and brafs- 

 yellow gold, have millakeiily defcribed the one fub-fpecies 

 for the other, and fome even fpeak of " grey-yellow gold 

 from Tranfylvania.' Tlie fub-divi(ion aliuiied to may K- 

 d^^emed inadmifTible ; but if it be at all adopted, by hi the 

 greater part of the native gold of Tranfylvania ard Hi;i - 

 giu-y, snd eonfequeatiy almoll: all cry!l.'..Iiy.cd gold, mull 

 neceifarily be referred to the light-coloured, and tliat found 

 in the fand of rivers to the deep-toloi:ivd fub-fpcti. s ; and 

 this not on account of their colour only, ufuallv indicativr 

 of differences in the chemical c(;mpofitiou of metals but 

 principally on account of tfie j;iognoliic rclatioiui. inuUr 

 which tliey refpcctivtly occur, and on \ihich great ilrcfc 

 apjjcars to be laid by W^erncr. 



2. Iron pyrite;-, containing not unfivqucntly aconfidinibi<? 

 portion of gold, in moll cafes invifibly diiperfcd and dil- 

 guifed, has by fome been conlidcnd as a fpecie;: of gold ore : 

 a dilh'nCtion to which (though fuch aur;f'.-.nis pyrites rre 

 often lubjccled to metallurgical treatment for cxtrattinc-tlu.i 

 metal, as will be feen hereafter) it cannot be coalidcrcd ::s 

 entitled. See V\b.iti.^, yiurif'rosu. 



T;«, 



