36s PHILOSOPItlCAL TRANSACTIONS. [anNO I67I. 



overshot our load. The remedy is easy, which is to sink nigher the hatch 

 wherein we last found shoad. 



At other times we find a new shoad, that is, two different shoads in one 

 hatch, as suppose in this hatch we find our shoad eight feet deep, in the next 

 we hope to find it at ten feet ; but at two or four we meet with a new shoad 

 and grewt, which we diligently observe, and at ten we meet with our first 

 shoad : then we have a certainty of another load above the former, and it may 

 be in training up to the second, we meet with the shoad of a third. Neither 

 is this dissonant to the opinion and practice of the ancient tinners, who affirm 

 that seven loads may lie parallel to each other in the same hill, but yet one 

 only master load ; the other six (three on each side) being the lesser concomi- 

 tants. So may five lie in like manner ; three are common. 



Every load has a peculiar coloured earth or grewt about it, which is found 

 likewise with the shoad in a greater quantity, the nearer the shoad lies to the 

 load, and so lessened by degrees about a quarter of a mile's distance ; farther 

 than which, that peculiar grewt is never found with the shoad. 



A valley may so lie, as at the feet of three several hills ; and then we may 

 find three several deads, i. e. common earth, or that loose earth which was 

 moved with the shoad in the concussion, but not contiguous to the load in its 

 first position, (which is also termed by us the run of the country,) with as 

 many different shoads in the midst of each. And here the knowledge of the 

 cast of the country, or each hill, in respect of its grewt, will be very necessary, 

 for the surer training of them one after the other, as they lie in order accord- 

 ing to the foregoing rules of essay hatches : for the uppermost will direct you 

 as to which hill to begin first. 



It may be, that after we have trained up the hill, instead of a load we find 

 nought but a bonny or squat ; which likewise have their shoad, whose form is 

 about two or three fathoms long and half as broad; few larger, most less: 

 which communicates with no other load or vein, neither does it send forth any 

 of its own ; but is entire of itself, whose extremities terminate without running 

 out into little innumerable strings, not lying within walls as loads ; although 

 they are in the shelf, whose surface is equal every where with that of the imagi- 

 nary shelfy one, and may go down five or six fathoms deep, more or less, and 

 there terminate; which squats are constantly wrought out with good advantage 

 to the workers when found ; neither is the tin of the baser sort. 



The Art and Manner of Digging up the Ore. 



The difficulty of this is not considerable, in comparison to that of training. 

 When we have found our load, the last essay hatch loses or rather exchanges 



