74 Extracts relating to Coal, Sfc 



rapidity. When a number of these kinds are situated from 

 each other in the direction of the strata, as above described : 

 or if the water docs not run forth as in springs, but only forms 

 a swamp, or an extension of stagnar.t water beneath the turf; 

 in either case, it may be depended upon that this water proceeds 

 from a stratum of Coal. 



If the stratum of Coal is not exposed to view, or cannot 

 be discovered by the first method of searching for the crop, 

 although the appearance of the other strata be very favourable, 

 and afford a strong probability of Coal being there; and if the 

 last-mentioned method of judging of the particular place where 

 the crop of the Coal may lie, by the springs of water issuing 

 from it, should, from the deficiency of those springs or other 

 circumstances, be thought equivocal, and not give a satisfac- 

 tory indication of the Coal, then a further search may be made 

 in all places where the outward surface, or the stratum of clay 

 or earth, is turned up bv ploughing, ditching, or digging, 

 particularly in the lower grounds, in hollows, and by the sides 

 of streams. These places should be strictly examined, to see 

 if any pieces of Coal be intermixed with the substance of the 

 superior last strata; if any such be found, and if they be 

 pretty numerous and in detached pieces, of a firm substance, 

 the angles perfect or not much worn, and the texture of the 

 Coal distinguishable, it may be concluded, that the stratum of 

 Coal to which they originally did belong, is at no gi^at dis- 

 tance, but in a situation higher with respect to the horizon ; 

 and if there be also found along with the pieces of Coal other 

 mineral matter, such as pieces of shiver or freestone, this is a 

 concurrent proof that it has come only from a small distance. 

 Though the two fore-mentioned methods should only have pro- 

 duced a strong probability, yet if this last-mentioned place, 

 where the pieces of Coal, &c. are found in the clay, be in a 

 situation lower than the springs; when this circumstance is 

 joined to the other two, it amounts to little less than a moral 

 certainty of the stratum of Coal being a very little above the 

 level of the springs But if, on the contrary, these pieces of 

 Coal are found more sparingly interspersed in the superior 

 stratum, and if the angles are much fretted or worn off, and 

 verv little of other kinds of mineral matter connected with them ; 

 it may then be concluded, that they have come from a stratum 

 of Coal situated at a greater distance than in the former case ; 

 and by a strict search and an accurate comparison of other 

 circumstances, that particular place may be discovered with as 

 much certainty as the other. 



After the place is thus discovered, where the stratum of 

 Coal is expected to lie concealed, the next proper step lo be 

 taken, is to begin digging a pit or hole there perpendicularly 



