Professor Hessel on the Crystallization of Ice ^ ^c, 159 



take place till the mass had returned to the state of rest, but 

 before the separation took place between the clay and the water. 

 The structure of the frozen mass varied in different experi* 

 ments. In every case, however, frozen mud and frozen clear 

 water could be distinguished from each other. But the latter 

 did not occur as a stratum at the upper part of the mass, but 

 was distributed through the substance of the frozen mud. 



1. The most common appearance was like that of small 

 quartz veins traversing in different directions a siliceous slate. 

 The same as in hand specimens of siliceous slate, when two of 

 the quartz veins meet one another, they traverse one another, 

 shift one another, or mutually cut each other off, &c. was ob- 

 served distinctly in the present instance. The principle that 

 the traversing vein is newer than the one traversed, could not be 

 easily demonstrated to be correct in these ice veins in the frozen 

 mud ; nor could the idea of the contemporaneous formation of 

 veins with the surrounding rock be admitted as unconditionally 

 correct. In these ice veins there was apparently a real cutting 

 across of one vein by another, so that the traversed vein be- 

 yond the traversing pursued its onginal course, or was diverted 

 somewhat from its position, but more frequently one was com- 

 pletely cut off by the other. Often we could suppose a true 

 wedging out of such a vein without a previously existing emptv 

 fissure promoting its formation. 



2. Often the water-ice was distributed through the frozen 

 mud like the quartz in the felspar of graphic granite. The 

 surface formed by cutting and polishing exhibiting, like the 

 latter Hebraic, Arabic, and Chinese characters ; and these were 

 still more characterised on the dark surface of the mud, than the 

 greyish-white quartz on the whitish felspar. 



3. Another mode of distribution of the water-ice in the frozen 

 mud, was its forming vertical plates, which were so grouped 

 that the surface of the mass of mud on its middle section, re- 

 sembled a concentrically radiated crystalline mass, the rays di- 

 verging from the centre outwards. Several of these groups of 

 rays were observed. Each ray projected to a considerable height 

 above the surface of the mud. 



During the formation of the veins, I sometimes observed also 

 that of hollow spaces. These were enclosed by three or more 



