io6 BOOK V. 



I have spoken of shafts, tunnels, and drifts. I will now speak of the 

 indications given by the canales, by the materials which are dug out, and by 

 the rocks. These indications, as also many others which I will explain, are 

 to a great extent identical in venae dilatatae and venae cii^nulatae with venae 

 profundae. 



When a stringer junctions with a main vein and causes a swelling, a 

 shaft should be sunk at the junction. But when we find the stringer inter- 

 secting the main vein crosswise or obliquely, if it descends vertically down 

 to the depths of the earth, a second shaft should be sunk to the point where 

 the stringer cuts the main vein ; but if the stringer cuts it obliquely the 

 shaft should be two or three fathoms back, in order that the junction may 

 be pierced lower down. At such junctions lies the best hope of finding the 

 ore for the sake of which we explore the ground, and if ore has already been 

 found, it is usually found in much greater abundance at that spot. Again, 

 if several stringers descend into the earth, the miner, in order to pierce 

 through the point of contact, should sink the shaft in the midst of these 

 stringers, or else calculate on the most prominent one. 



Since an inclined vein often lies near a vertical vein, it is advisable 

 to sink a shaft at the spot where a stringer or cross-vein cuts them both ; 

 or where a vena dilatata or a stringer dilatata passes through, for minerals 

 are usually found there. In the same way we have a good prospect of finding 

 metal at the point where an inclined vein joins a vertical one ; this is why 

 miners cross-cut the hangingwall or footwall of a main vein, and in these 

 openings seek for a vein which may junction with the principal vein a few 

 fathoms below. Nay, further, these same miners, if no stringer or cross- 

 vein intersects the main vein so that they can follow it in their workings, 

 even cross-cut through the solid rock of the hangingwall or footwall. These 

 cross-cuts are likewise called " Kprnm!," whether the beginning of the 

 opening which has to be undertaken is made from a tunnel or from a drift. 

 Miners have some hope when only a cross vein cuts a main vein. Further, 

 if a vein which cuts the main vein obliquely does not appear anywhere 

 beyond it, it is advisable to dig into that side of the main vein toward which 

 the oblique vein inclines, whether the right or left side, that we may ascer- 

 tain if the main vein has absorbed it ; if after cross-cutting six fathoms it 

 is not found, it is advisable to dig on the other side of the main vein, that 

 we maj' know for certain whether it has carried it forward. The owners 

 of a main vein can often dig no less profitably on that side where the vein 

 which cuts the main vein again appears, than where it first cuts it ; the 

 owners of the intersecting vein, when that is found again, recover their title, 

 which had in a measure been lost. 



The common miners look favourably upon the stringers which come 

 from the north and join the main vein ; on the other hand, they look 

 unfavourably upon those which come from the south, and say that these do 

 much harm to the main vein, while the former improve it. But I think 

 that miners should not neglect either of them : as I showed in Book III, 

 experience does not confirm those who hold this opinion about veins, so now 



