AND THEIR MEETING WITH GRANITE. 85 



concave towards the centre of the earth *. At the same time, 

 no other force being applied, any two particles which lay 

 with respect to each other, so that the straight line joining 

 them were horizontal, and at right angles to the direction of 

 that active force, would retain their relative position, and of 

 course that line would maintain its original straightness and 

 horizontality ; and thus the forces exerted being simple, or, if 

 compound, tending, as just stated, to produce a simple result, 

 the beds would acquire the simple curvature ascribed to them 

 by Mr Play fair, and which belongs to them, in the imme- 

 diate neighbourhood of Fast Castle ; whereas, in Galloway, 

 and in some parts of our coast, particularly near Gun's Green, 

 to the eastward of Eyemouth, where the curvature deviates 

 from that simple character, and becomes in the utmost degree 

 irregular, we must conceive the force to have been more com- 

 plicated, or most probably to have acted at successive pe- 

 riods. 



This conjecture no sooner occurred, than I endeavoured to 

 illustrate my idea by the following rude experiment, made 

 with such materials as were at hand. Several pieces of cloth, 

 some linen, some woollen, were spread upon a table, one 

 above the other, each piece representing a single stratum ; 

 a door (which happened to be off the hinges) was then laid 

 above the mass, and being loaded with weights, confined it 

 under a considerable pressure, (fig. 3. Plate IV.), two boards 

 being next applied vertically to the two ends of the stra- 

 tified 



* I am aware, that this expression of parallel curves is irregular ; but I can 

 find no other mode of conveying the idea. It is not easy to trace, a priori, what 

 form would be assumed by these beds, supposing the whole to be held down by 

 a force so powerful as to prevent any vacuity. It is enough, however, for our 

 present purpose, that the forms of nature correspond with those obtained in an 

 experiment soon to be mentioned. 



