240 Remarks on the Moving Rocks of Salishury. 



although very firmly fixed in the stones and gravel. Duriag 

 the past winter the rocks have moved but very little, owiag 

 to the mildness of the season. From December 1823, to 

 February 1 826, the rock above mentioned has moved two 

 and a half feet, which is much less than in former years, for 

 the same reason ; besides it has now become more deeply 

 imbedded in the gravel, and the full force of the expanding 

 ice is not exerted upon it. 



Since the attention of the public was called to this subject 

 in 1822, many similar facts have been observed in different 

 parts of New England. In the mountain pond in this town, 

 the rocks within reach of the ice are annually moved toward 

 the shore, forming an artificial dike of considerable extent. 

 The same has been observed in ponds in Sharon and other 

 places. There is no longer any doubt or dispute on the 

 subject, and the cause is as obvious as that of any natural 

 phenomenon which occurs. 



The remarks on this subject by J. Wood, Esq., in the last 

 number of the Journal are highly ingenious and plausible, 

 but I fear wholly unsupported by evidence. I have never 

 seen ice "grappling a rock" in the maimer he mentions, and 

 I believe it is the general opinion that ice first melts around 

 the rocks, leaving them, when the ice breaks up in the spring, 

 untouched by it. Your correspondent remarks that, " as 

 the earth contains a greater portion of caloric than the water, 

 the ice dissolves most rapidly nearest the shores of the 

 pond." 1 think it might with the same propriety be added, 

 that as stone is a tolerably good conductor, the rocks serve 

 as conducting media, conveying the caloric from the adjacent 

 earth and water to the ice and surrounding atmosphere, thus 

 melting the ice around their edges. At any rate, the moving 

 rocks of this town are generally of such shape that they can 

 not well be " grasped" by the ice, being very shelving ; and 

 that they are not supported in this manner, and thus driven 

 about by the winds and waves, is evident from the fact, that 

 the ice thaws around them (it being near the shore) before it 

 does in other parts of the pond. It is however undoubtedly 

 true that rocks of considerable size are sometimes moved by 

 large bodies of ice being driven forcibly against them. 



The expansive power of freezing water has been so ably 

 treated by Mr. Adams in the last number of the Journal, that 

 it is unnecessary to dwell upon it here. It has been found, 

 from experiments performed at Edinburgh, to burst the 



