BOOK V.

107

again I could furnish examples of each kind of stringers rejected by thecommon miners which have proved good, but I know this could be of littleor no benefit to posterity.

If the miners find no stringers or veins in the hangingwall or footwall ofthe main vein, and if they do not find much ore, it is not worth while toundertake the labour of sinking another shaft. Nor ought a shaft to be sunkwhere a vein is divided into two or three parts, unless the indications aresatisfactory that those parts may be united and joined together a little later.Further, it is a bad indication for a vein rich in mineral to bend and turnhither and thither, for unless it goes down again into the ground vertically orinclined, as it first began, it produces no more metal; and even though itdoes go down again, it often continues barren. Stringers which in theiroutcrops bear metals, often disappoint miners, no metal being found in depth.Further, inverted seams in the rocks are counted among the bad indications.

The miners hew out the whole of solid veins when they show clear evidenceof being of good quality ; similarly they hew out the drusy 4 veins,especially if the cavities are plainly seen to have formerly borne metal, orif the cavities are few and small. They do not dig barren veins throughwhich water flows, if there are no metallic particles showing ; occasionally,however, they dig even barren veins which are free from water, becauseof the pyrites which is devoid of all metal, or because of a fine black softsubstance which is like wool. They dig stringers which are rich in metal,or sometimes, for the purpose of searching for the vein, those that are devoidof ore which lie near the hangingwall or footwall of the main vein. Thisthen, generally speaking, is the mode of dealing with stringers and veins.

Let us now consider the metallic material which is found in the canalesof venae profundae, venae dilatatae, and venae cumulatae, being in all theseeither cohesive and continuous, or scattered and dispersed among them,or swelling out in bellying shapes, or found in veins or stringers whichoriginate from the main vein and ramify like branches ; but these latter veinsand stringers are very short, for after a little space they do not appear again.If we come across a small quantity of metallic material it is an indication ;but if a large quantity, it is not an “ indication,” but the very thing forwhich we explore the earth. As soon as a miner who searches for veinsdiscovers pure metal or minerals, or rich metallic material, or a greatabundance of material which is poor in metal, let him sink a shaft on thespot without any delay. If the material appears more abundant or of betterquality on the one side, he will incline his digging in that direction.

Gold, silver, copper, and quicksilver are often found native 5 ; lessoften iron and bismuth ; almost never tin and lead. Nevertheless tin-stonels not far removed from the pure white tin which is melted out of them, andgalena, from which lead is obtained, differs little from that metal itself.

Now we may classify gold ores. Next after native gold, we come to the

l Cavernos. The Glossary gives drusen, our word drusy having had this origin.

& Purum ,—“ pure.” Interpretatio gives the German as gedigen ,—“ native.”