Remarks on the moving of rocks hy Ice. 145 



from the shore on all sides, and is thus converted into an 

 island, moored by the rocks. 



The earth on which they rest, being soft nnud, nauch 

 less power is requisite to raise thenn from their beds, or to 

 project them alongon (his slippery surface, than would be 

 required to raise or move them on dry, stony, or gravelly 

 ground. By the abundant rains of the spring, and the 

 dissolution of the snow and ice, the water of the pond is 

 accumulated, whereby the island of ice, with every thing 

 which remains attached to it, is raised until its strength is 

 overpowered by the pressure. And we know that a single 

 rood of ice of but a few inches in thickness will sustain 

 an immense weight while lying on the surface of the 

 water. 



A strong wind then, blowing from any quarter, will 

 agitate the water between the shore and the ice, as also 

 that under the ice. Thus the increase of the water, or 

 the raising of the surface of the pond, will loosen, or ex- 

 tract from their beds all those rocks whose weight and 

 depth in the earth are not too great for the strength of the 

 ice ; and the force of the wind, acting upon the water and 

 the ice, will propel them toward the opposite shore. — 

 Like the ship therefore, whose anchor is unable to sustain 

 the force of the tempest, the floating island is driven from 

 its moorings. Thus forced toward the shore, the ice 

 gradually dissolves on the side nearest the land, so that 

 the rocks yet attached to the ice, and partially resting in 

 the mud, are dragged nearer and nearer to the shore, 

 propelling the mud before them, until the island be- 

 comes so diminished, that with the power of the wind 

 and the waves, it can no longer drag its anchors, and 

 therefore deposits them near the margin of the pond. It 

 is therefore a natural consequeiyce that they leave a track 

 behind them by which their progress may be traced. 



If this exposition is not the true one, it may, at least, 

 answer until a better one can be given. 



Vol. IX.— No. 1. 19 



