ON THE PRE-NORMAN SCULPTURED STONES OF DERBYSHIRE. I 75 



XV., 7) for two purposes — first, because it is an excellent example 

 of what is called the Stafford Knot, and is one of one or two 

 evidences that this knot was not unused in Derbyshire, and next, 

 because — though this does not appear in the rubbing — it shows 

 unusually well a feature which I notice in almost all these stones 

 when they are considerably weathered. The grooves between the 

 bands are neither more nor less than a row of little circular holes, 

 showing that the original cutter, having traced his pattern, worked 

 with a drill, and having drilled rows of holes where the grooves 

 were to be, he broke away with his pick the walls of separation 

 between the circular holes, thus producing a groove. The groove 

 was so deep that when the very high relief which these stones 

 must have had was fresh, it was not noticed that at the bottom of 

 the groove the marks of the drill were still to be seen. But now, 

 when the weather has taken off perhaps three-quarters of an inch 

 of surface over the whole stone, the secrets of the process are laid 

 bare at the bottom of the groove. It is quite probable that they 

 drilled to different depths according to the amount of relief 

 required, as the modern sculptor of a bust does. In several cases 

 of rude work, the course of the drill can. be followed down the 

 vertical edges of the bands from top to bottom. I may mention 

 that I think I have found the way in which our ancestors drew the 

 beautiful spirals that ornament these crosses. You may produce 

 precisely the same spiral by taking on a diameter line two points 

 near each other for centres ; with the left hand point as centre 

 describe a semi-circle on one side of the line, with the right hand 

 point as centre, and as a radius the distance from this point to the 

 nearer extremity of the other semi-circle, describe a semi-circle on 

 the other side of the line. Then pass to the first centre and 

 describe a still smaller semi-circle on the original side of the line, 

 and so on. One thing I think is clear, that none of these spirals 

 are either involutes or evolutes, though either of these figures 

 might very well have been discovered by persons working with the 

 most ordinary gravers. Before leaving this fragment, I must call 

 attention to the very remarkable ornament on its edge, almost like 

 the ammonites of Saint Hilda ; this is quite unique in my experi- 



