VOL. VI.] PHILOSOPHICAL TRANSACTIONS. ^^ 



its name for that of a tin-shaft, or tin-hatch, which we sink down about a 

 fathom, and then leave a httle long square place, termed a shamble, and so 

 continue sinking from cast to cast, i. e. as high as a man can conveniently 

 throw up the ore with a shovel, till we find either the load to grow small, or 

 degenerate into some sort of weed, which are divers ; as mundic, or maxy 

 (corrupted from marchasite) of three sorts ; white, yellow, and green : daze, 

 white, black, and yellow, being a kind of glittering stone, enduring the fire : 

 iremould, black, and rusty : caul, red: cHster, blood-red, and black. 



Then we begin to drive either west or east, as the goodness of the load, or 

 conveniency of the hill invite ; which we term a drift, three feet over, and 

 seven feet high ; so as a man may stand upright and work ; but in case the 

 load be not broad enough of itself, as some are scarce half a foot, then we 

 usually break down the deads on one side of the load, and after we begin to 

 rip the load itself. [By deads here are meant that part of the shelf which 

 contains no metal, but encloses the load as a wall between two rocks, and not 

 as that which was mentioned in the concussion, as in training.] 



The instruments commonly used in mines, that serve for ripping the loads, 

 and breaking the deads, and landing both the ore and deads, are ; 1 . A beele 

 or Cornish tubber {i. e. double points) of 8lb. or lOlb. weight, sharpened at 

 both ends, well steeled and holed in the middle. It may last in a hard coun- 

 try half a year, but new pointed every fortnight at least. 2. A sledge, flat 

 headed, from lOlb. to 20 lb. weight ; will last about seven years, new ordered 

 once a quarter. 3. Gadds or wedges of 21b. weight, four square, well steeled 

 at the point, will last a week ; then sharpened after two or three days. 

 4. Ladders. 5. Wheelbarrows, to carry the deads and ore out of the drifts 

 or adits to the shambles. 



The proportion of men is, two shovelmen, three beelemen, which are as 

 many as one drift can contain, without being a hinderance to each other. The 

 beelemen rip the deads and ore ; the shovelmen carry it off, and land it by 

 casting it up with shovels from one shamble to another, unless it be where we 

 have a winder with two keebles (great buckets made like a barrel with iron 

 hoops, placed just over the then termed wind hatch,) which as one comes up, 

 the other goes down. 



A great deal of this skill consists in the exact knowledge and observation of 

 the loads dipping ; for which we have this general rule : That most of our tin 

 loads, which run from west to east, constantly dip towards the north ; some- 

 times they underlie, that is, slope down towards the north, three feet in eight 

 perpendicular ; which must be observed, that we may exactly know where to 

 sink an air-shaft, when occasion requires ; yet in the higher mountains of 



VOL. I. 4 C 



