of the red oxyd of Copper and arseniated Iron. 25 



principally between the sixty-six and eighty-six fathom levels, in 

 considerable quantity, often in well-defined crji^stals, and occasionally 

 intermingled with native copper. Above it, the lode abounded with 

 fluate of lime, frequently very solid, and so pure, that they, whose 

 business it is to assay copper for the miner and the purchaser, 

 preferred it as a flux to that of any other mine. Among this fluate 

 of lime, and sometimes intimately mingled with it, considerable 

 quantities of the yellow copper ore were found, and some arsenical 

 pyrites containing 4 or 5 per cent, of copper, though comparatively 

 little of that gossan, which, as will presently be noted, constituted 

 the greater part of the Muttrell Lode ; nor was the arseniate of 

 copper discovered in any part of this lode, west of the junction of it 

 with the Muttrell Lode. 



The Muttrell Lode is one, to which no other lode hitherto dis- 

 covered in the County of Cornwall bears any analogy. Throughout 

 almost the whole length of its working, but particularly in that part, 

 above, below, and in which v/as discovered the great deposit of 

 red oxyd of copper, with the beautiful varieties of which this mine 

 has enriched the cabinet of the mineralogist, this lode abounded iri 

 an ochreous substance, frequently accompanied by quartz, which 

 from its appearance may be termed an argillaceous oxyd of iron ; and 

 which, sometimes for a considerable length and depth, constituted 

 •alone the great body of the lode. This substance is always con- 

 sidered by the miner as an indication of neighbouring riches ; it 

 is technically called gossan, and is denominated kindly, or very kindly, 

 in proportion to the darkness of its hue, and the looseness of its 

 texture. Through this gossan they sunk in the Muttrell Lode 

 ■forty-six fathoms, and almost as many above the adit, before they 

 arrived at any considerable quantity of the red oxyd of copper, 

 -which afterwards continued through a space ten jE^thoms in depth, 



D 



