Rev. Mr Eisdale's Observations on Ground- Ice. 173 



accumulate much more abundantly upon such parts of the stones 

 as stood most opposed to the current (where that was not very 

 rapid), below the little falls, or very rapid parts of the river.'* 



These are by far the most important observations that have 

 been made on the subject of ground-ice. M. Arago is so much 

 struck by them, that after having concluded his own theory he 

 says, " It is not certain that the little particles, mentioned by 

 Mr Knight, do not play an important part in this phenomenon, 

 which I have entirely overlooked." I verily believe they do ; 

 only one element is wanting in the catalogue of Mr Knight's 

 observations to decide my opinion, and that is, the state of the 

 atmosphere during the preceding night. I am persuaded that 

 it had been loaded with hoar-frost, and its precipitation into the 

 river formed the floating spicuta which he observed ; they could 

 have no other origin ; and their being brought into contact with 

 the stones by the gyrations of the stream, is exactly what I had 

 given two years ago as the theory of the formation of ground- 

 ice, by the congelation and precipitation of the moisture of the 

 atmosphere. 



It is always delightful to explore the mysteries of nature, and 

 the Author of our being has provided in such researches un- 

 bounded exercise for the highest powers of our understanding 

 and reason. Even brute matter gives us some idea of the im- 

 mensity of its Creator ; for notwithstanding the immense strides 

 that have been made in investigating the properties of matter, 

 we may be said to^be at this moment only on the threshold of 

 science ; and future generations, if the mind goes on to improve, 

 will look back on our most profound researches merely as form- 

 ing the rude elements of that more perfect knowledge which 

 they will have reached. Perhaps much remains to be known 

 even with regard to the common phenomena to which I have 

 this day directed the attention of this meeting; and although I 

 think we have nearly reached the solution of our problem in the 

 process of freezing, yet that you may not think the mysteries 

 of congelation exhausted, I conclude with mentioning a fact, 

 which the illustrious Frenchman, whom I have so often quoted, 

 leaves without even attempting an explanation. " During the con- 

 gelation of the bottom of the Aar, M. Hugi immersed pitchers 

 filled with hot and cold water ; the first, on being brought up. 



