460 Br. K. Landor — On Ground-ice as a Carrier. 



or whether they were brought from the bottom by ground-ice. As 

 soon as the tubular character of the ice is lost, the power of dis- 

 criminating the origin of the stone is lost also. I have seen in the small 

 rivers that form the Thames a vast number of pebbles and stones, as 

 big as a foot diameter, carried away by ground-ice. Some years since 

 I watched the rapid portion of the rivers daily, and frequently saw the 

 ice rise with stones attached. A warm sun^ after a zero frost, about 

 10 A.M., is the proper time and the proper condition for seeing the 

 rise of the ice ; and some patience is necessary in waiting, for what 

 will not rise one day may rise the next, and the colder the night, the 

 nearer mid-day, when the sun has most power, the phenomenon 

 occurs. These blocks, with adhering stones, travel down the river 

 in the spring, but how far they go must depend on their power to 

 keep their mass unbroken. When I was in London, I thought it 

 would be impossible for them to reach the lakes before being broken 

 up, at weirs, or by knocking against each other. But whilst here — 

 Aniherstburg — last winter, when the ice broke up twice in the 

 Detroit river, I saw masses of ice with boulders such as I named, 

 and pebbles in vast quantities adherent, float past this asylum, which, 

 I have no doubt, came from the ground-ice formed in some or other 

 of the rivers that empty into Lake Huron or Lake St. Clair. 



" Before I consider the results that follow from this subject, I will 

 say a few words on the difficulties of the formation of ground-ice. 

 The first that presents itself is the congelation of water at the 

 bottom, when we all know that the peculiarity of water, when at 

 rest, is, that it cannot freeze at the bottom until the whole mass is 

 frozen from the surface downwards. It is needless to state to you 

 the nature of the changes that take place in water when it alters its 

 temperature to the freezing-point. Knowing them, it is hard to 

 conceive how the first act of congelation takes place at the bottom, 

 without the ice at once rising to the surface. It seems clear that the 

 first condition in the formation of ground-ice must be, that the tem- 

 perature of the stones at the bottom falls below freezing-point ; but 

 it is not clear why the temperature should so fall, covered as they 

 are by water that is above the temperature of freezing-point. I have 

 never seen the water below 32° when taken out of the river ; and it 

 is clear that if it were below that point, as soon as it is taken into a 

 vessel it ought to become flaky with atoms of ice the moment it is at 

 rest in that vessel. Whilst running rapidly, water may not congeal, 

 even if slightly below 32°, but at rest it should do so constantly. 

 Moreover, if the water is below 32°, which I have never observed, 

 the whole mass of the river must be below 32°, for it is impossible to 

 suppose that it becomes so just as it begins to run over the shallows, 

 and ceases to be so when it reaches the still depths again ; for it 

 must be above 32° in the deep parts of the river, or else it would 

 become ice ; and it should be colder in the depths, because it is in 

 less agitation than in the shallows. Motion is warmth in all bodies, 

 and it is the same in water as in solids. Motion is warmth, and 

 therefore there ought to be more warmth in the rapids than in the 

 still water; all which considerations make the subject of ground-ice 



