96 September 1748. 



fince autumn, when it firft fettled on the banks 

 of the river, fall out of the ice upon the rocky 

 bank, and are from thence carried into a cleft or 

 crack by the water. Thefe pebbles are then 

 continually turned about by the water, which 

 comes in upon them, and by this means they 

 gradually form the hole. The water at the fame 

 time polifhes the ftone by its circular motion 

 round it, and helps to make the hole or cavity 

 round. It is certain, that, by this turning and 

 toffing, the ftone is at laft unfit for this purpofe : 

 but the river throws commonly every fpring other 

 ftones inftead of it into the cavity, and they are 

 turned round in the fame manner. By this 

 whirling, both the mountain and the ftone afford 

 either a fine or a coarfe fand, which is wafhed 

 away by the water, when in fpring, or at other 

 times, it is high enough to throw its waves into 

 the cavity. This was the opinion of Mr. Bar- 

 tram about the origin of thefe cavities. The 

 Royal Society of Sciences at London, has given a 

 favourable reception to, and approved of them. * 

 The remarks which I made in the fummer of 

 the year 1743, during my ftay at Land*s-Ort, in 

 my country, will prove that I was at that time 

 of the fame opinion, in regard to thefe holes. I 

 have fince further explained this opinion in a 

 letter to the Royal Academy of Sciences ; and 

 this letter is ftill preferved in the Academy's Me- 

 moirs, which have not yet been publifhed. But 



* How far this approbation of the Royal Society ought to be 

 credited, is to be uuderftood from the adverdfements publifhed at 

 the head of each new volume of the Philofophical Tranfaftions. 



