74 
over the lower water, which is to he supposed at rest. 
The effect of a drop would he to knock some of the 
moving water into that which is at rest, and a correspond- 
ing quantity of water would have to rise up into the moving 
layer, so that the upper layer would lose its motion hy com- 
municating it to the water helow. Now when the surface 
of water is disturbed hy waves, besides the vertical motion 
the particles move backwards and forwards in a horizontal 
direction, and this motion diminishes as we proceed down- 
wards from the surface. Therefore in this case the effect of 
rain drops will be the same as in the case considered above, 
namely to convey the motion which belongs to the water at 
the surface down into the lower water where it has no effect 
so far as the waves are concerned, and hence the rain would 
diminish the motion at the surface, which is essential to the 
continuance of the waves, and thus destroy the waves. 
“On the Stone Mining Tools from Alderley Edge,’' by 
Professor W. Boyd Dawkins, F.E.S. 
Discovery. 
In May, 1874, Mr. H. Wilde and myself happened to 
take a walk to the new excavations which were in progress 
at the copper mines at Alderley Edge, which penetrate the 
rock on the east side of “the Street Koad,” leading to 
Alderley. The Lower Keuper sandstone in that place is 
impregnated with carbonate of copper, in search of which 
tunnels had been driven into the base of the hill in the 
main parallel to the strata, having there a depth to the 
west of about 29°. In following the ore from the deep 
upwards the miners had worked their way to the surface, 
on the hillside immediately above the heaps of refuse near 
the reducing tanks, and laid bare a considerable portion of 
the rock. While walking over this surface, which was fan- 
tastically hollowed, a worked stone happened to catch 
