Note 20 — PETER KALM’s TRAVELS. (continued 2)

Mr. Bartram related, that on his journeys to the northern English colonies, he had discovered great holes in the mountains on the banks of rivers, which according to his description, must exactly have been such giants pots,20 as are to be met with in Sweden, and which I have described in a particular dissertation read in the Royal Swedish Academy of Sciences. Mr. Bartram has likewise addressed some letters to the Royal Society at London upon this subject. For some people pretended, that these holes were made by the savages, that they might in time of war hide their corn and other valuable effects in them. But he wrote against this opinion, and accounted for the origin of these cavities in the following manner. When the ice settles, many pebbles stick in it. In spring when the snow melts, the water in the rivers swells so high that it reaches above the place where these holes are now found in the mountains. The ice therefore will of course float as high. And then it often happens, that the pebbles which were contained in it, ever since autumn when it first settled 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. These 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 same time polishes the stone by its circular motion round it, and helps to make the hole or cavity round. It is certain that by this turning and tossing, the stone is at last unfit for this purpose; but the river throws commonly every spring other stones instead of it into the cavity, and they are turned round in the same manner. By this whirling both the mountain and the stone afford either a fine or a coarse sand, which is washed away by the water when in spring, or at other times it is high enough to throw its waves into the cavity. This was the opinion of Mr. Bartram about the origin of these cavities. The Royal Society of Sciences at London, has given a favourable reception to, and approved of them.21 The remarks which I made in the summer of the year 1743, during my stay at Land’s-Ort, in my country, will prove that I was at that time of the same opinion, in regard to these holes. I have since further explained this opinion in a letter to the Royal Academy of Sciences; and this letter is still preserved in the Academy’s Memoirs, which have not yet been published. But there is great reason to doubt, whether all cavities of this kind in mountains, have the same origin.