Manufacture of Sulphat of Iron. 329 



Del, into which by its inclination the mine discharges the 

 wash of every shower, together with the natural oozing 

 from the hill above. A trough conveys the fluid from the 

 channel to the boilers. To increase the effect of this natu- 

 ral brook of copperas, the ore has been broken into large 

 fragments, and heaped along the upper side of the chan- 

 nel, there to undergo a slow decomposition precisely as it 

 does upon the scaffolds mentioned above. 



The mine where it has not been opened is covered with 

 oxid of iron which consists principally of incrustations of 

 vegetables. 



In the part where I examined these incrustations they are 

 about three feet deep. The vegetables seem to have been 

 enveloped by a thin uniform crust, but having decayed and 

 disappeared the crust remains an empty mould or pattern of 

 the vegetable. The general figure of the vegetable is pret- 

 ty well preserved in the external form of incrustation ; but 

 the internal cavity is wonderfully perfect, the sinuosities 

 of the bark, the veins of the leaves and the striae of the 

 buds are preserved to microscopic minuteness. The im- 

 pressions are so perfect that it is difficult for one to con- 

 vince himself that the real vegetable is not there. All the 

 vegetables that we should expect to find upon a given spot 

 of ground, in the woods, seem to occur there. I could in 

 general recognize the species and even the varieties. 

 Among the specimens I obtained were the following : hem- 

 lock branches and cones; nuts, burrs, and leaves of the 

 beech ; hazel nuts and a species of golden rod which I re- 

 cognized by a peculiar swelling often produced upon this 

 plant by an insect. I could not ascertain that any animals 

 had ever been found incrusted. The incrustations are divi- 

 ded into several strata by layers of oxid, which have a 

 structure so compact as to present a fracture almost or quite 

 vitreous. 



The superintendant told me that four men manufactured 

 one hundred tons of copperas in a year, besides carrying on 

 the business of a small farm. 



A small quantity of the ore has been found which had 

 undergone a spontaneous decomposition and was thought to 

 be very rich. The superintendant told me, that a barrel of 

 it afforded three hundred and thirty-three pounds of coppe- 

 ras. When I considered the quantity of iron the liquor dis- 



VoL. Ill No. 2. 42 



