138 ALEXANDER VON HUMBOLDT. 



had ever dared to hope. The documents of the sixteenth 

 century, recently discovered, which I have been studying with 

 the greatest assiduity, have given me the right clue. My various 

 predecessors in the superintendence of these mines have all 

 failed for want of this source of information. An expenditure of 

 14,000 florins in eight years has scarcely produced 150 tons of 

 gold ore, while I have procured from this mine alone in one 

 year, and with the labour of only nine men, 125 tons of gold 

 ore at a cost of barely 700 florins. Some experiments that 

 have been made show that it will readily amalgamate. The 

 mining commission of Berlin assured Hardenberg last year 

 that a hundredweight of gold ore is scarcely worth three 

 kreutzers, while this year I have reported the value of it to 

 be twenty-four kreutzers. You see, my dear friend, that I am 

 becoming quite a boaster. But I speak in this strain only to 

 you. The district of Naila is progressing as rapidly as that 

 of Hammsdorf is declining. The mines of the latter furnish 

 from 100 to 112 tons of iron-stone, while ours produce 188. 

 They employ five or six men only in the workings, whereas we 

 have twenty men, and, in the case of one mine, as many as 

 forty men at work. Our results this year are in iron to the 

 value of 163,000 florins, in vitriol to 28,000 florins, and in 

 cobalt, tin, antimony, copper, grey copper ore, and alum con- 

 jointly, to the amount of 300,000 florins. This is certainly an 

 ample return with only 350 miners. At Steben I have at 

 length commenced the working of the Frederick- William 

 gallery, the preparations for which kept me busy the whole 

 summer. I made out a very elaborate estimate of the cost, 

 amounting to 20,000 florins, in ( which everything is included, 

 down to the plank-nails ; it is an opus opemtum which I must 

 send you some day, together with a history of the most recent 

 copper-mine at Steben. The new copper workings are ever) 7 - 

 where improving, and I am sure that with the Frederick- 

 William gallery, which can also be made navigable, they will 

 in time again yield from 100 to 150 tons of pure copper. But 

 enough of this boasting.' l 



An attack of intermittent fever, caught by exposure to the 



1 As a means of comparison, it will be well here to give a passage from a 

 treatise "by Heinitz on the mineral products of the Prussian States, ' Ab- 



