ON THE FORMATION OF ICE AT THE BOTTOM OF 



THE WATER. 



BY M. ENGELHARDT, DIRECTOR OF THE FORGES OF NIEDERBROXX, (LOWER RIUXE.) 



TiTJisIated for the Smithsonian Institution from tlie " Annales de Chimie et de Physique," 



Paris, I860. 



There are not a few natural phenomena wbicli are better known to the people 

 than to the learned; and the reason of this is simple. The man of the people, 

 always in quest of the means of bettering his condition, observes a phenomenon 

 not with a view to investigate its cause, but to derive from it some practical 

 benefit. The savant, on the contrary, withdrawn from nature in the meditations 

 of the closet, usually recurs to practical experience only when he is led to do so 

 by the speculations of theory, and often refuses to recognize the facts which do 

 not square with his preconceived ideas. 



Hence it has happened that sundry physicists, Nollet, Mairan, and others who 

 have followed them, have denied a phenomenon well known to all the watermen 

 and frequenters of the great rivers of the centre and north of Europe : I mean 

 the ice which, in severe frosts, forms at the bottom of rivers, and which the 

 Germans call grundcis, ice of the bottom. 



The Rhine and the Danube, rivers with a rapid current, do not freeze like the 

 Seine by being covered with a plane and uniform stratum ; they bear along large 

 blocks of ice which cross and impinge upon one another, and becoming thus 

 Leaped together, finally barricade the river. It is a grand spectacle, when the 

 Rhine is thus charged, to see these countless drifts adjust themselves in their 

 relative position, where they unite by c )ngelation, and convey the idea of the 

 fall of some mountain which has covered the plain with rocks of every dimen- 

 sion. But it is not this accumulation of ice drifts in the Rhine which is of itself 

 the cause of danger ; it is, on the contrary, the debacle or breaking up which is 

 often productive of calamitous consequences. When this debacle commences in 

 the upper part of the river, above the point where the latter is completely frozen, 

 the masses of ice, drifting with the current and unable to pass, are hurled upon 

 those already soldered together; thus an enormous barrier is formed which the 

 water, arrested in its course, canrot pass over, and hence overflows to the right 

 and lett, breaking the dikes, inundating the plains, and spreading devastation 

 and suffering far and near. 



The disasters caused by the debacles of the Rhine have taught the riparian 

 inhabitants to observe attentively the facts which may serve them as a prog- 

 nostic, and put them on their guard against the irruption of the ice. It is thus 

 that they have been led to observe the grundeis — that is to say, the ice formed 

 at the bottom of rivers, for it is this ice which, in becoming detached from the 

 bottom and risii^ towards the surface, unites itself to the under surface of the 

 masses already in place, and by further embarrassing the discharge, exposes 

 the country to inundation. 



Being intrusted with the direction of important Avorks, I felt it the more incum- 

 bent on me to observe with care the daily phenomena which might have an influ- 

 ence on our labors, and it is from having followed them with great attention that I 

 have found, ds I believe, the true cause of the presence of ice at the bottom of rivers. 



Let us first consider the phenomenon historically as we find it related by 



