128 Professor Merian on Ground-Ice , &c. 
remarks, serve to shew, that the ideas indicated by the German 
name grundeis, are generally diffused among the country people 
in England, and present a detailed relation of facts furnished by 
an observer, whose accuracy can be relied upon ; and, from 
these facts we may conclude, that there forms, at the bottom of 
running water, not only an ice disposed in tufts, but also, when 
the circumstances are favourable, a layer of compact ice. 
Of the more recent observations upon this subject, he men- 
tions that of Mr Streake, who relates, that, in February 1806, 
at Pillau, chains of iron, six feet in length, which had remained 
for a long time lost at the bottom of the water, a cable thirty fa- 
thoms long, and stones weighing from three to six pounds, were 
raised to the surface, inclosed in a thick envelope of ice ; and 
that an anchor, after having remained an hour in the water, was 
taken out covered with a layer of ice. 
In conclusion, the author observes, that, after having addu- 
ced proofs of the formation of ice at the bottom of running wa- 
ter, he has to remark, that it cannot by any means be pretend- 
ed, that this ice, once raised from the bottom to the surface, does 
not augment in a remarkable manner. This result, on the con- 
trary, appears probable : because the pieces of ice which are al- 
ready found at the surface, being at least as cold as the bot- 
tom, must present nuclei, whose presence contributes to the 
freezing of the water. This freezing of the surface will espe- 
cially extend, when, from any circumstance whatever, the ground- 
ice may be stopped in some places, and will there form a more 
or less compact mass. Nor does he deny, that, in certain cases, 
ice may be formed, even at the surface of running water ; but 
he thinks it sufficiently established, that ice is formed at the bot- 
tom of brooks and rivers ; and the characters of this ice being 
entirely similar to those of the ground-ice which floats at the sur- 
face, it is more than probable that they have a common origin, 
and a common mode of formation. 
below, which he found six lines thick, but much more spongy and porous than the 
other. The lower ice was in contact with the upper, at the edge of the river, but 
it was always more distant from it, in proportion as the water became deeper, be- 
cause the frost had taken place close upon the ground. When the bottom ice rose in 
the water, in consequence of its lightness, it always carried with it sand and stones. 
He adds, when it is very thick, it carries with it the wicker baskets loaded with 
stones, which are placed at the bottom of the water to catch fish. A number of 
other observations, tending to the same general result, are also given by him. 
