﻿506 M. A. Heim on Glaciers. 



of the cavity a splendid system of transverse fissnres is ob- 

 tained, exactly as they are formed in neve-plateaux, which 

 are the boundaries of glaciers. This system of fissures can 

 never be replaced by displacements. 



With all this a variety of thoughts, leading to further expe- 

 riments, connect themselves — for instance, about an arrange- 

 ment of semiliquid masses in a systematic series according to 

 mechanical principles, &c. Perhaps I shall subsequently re- 

 sume the subject. The experiments, still very incomplete, could 

 not be further continued on this occasion ; for as in a mountain- 

 stream the rubble stones move more slowly than the water, so 

 our labours are always outstripped by time. 



3. On Structure. 



In order to prove that the structure of glacier-ice (the blue 

 bands) is not derived from the stratification of the snow, Pro- 

 fessor Tyndall searched for places where the structure and the 

 stratification might be seen together, and after long searching 

 he found them. On the Upper Rhone Glacier, in the summer 

 of 1869 we had continual opportunities of repeating and con- 

 firming his observation. In almost all the fissures the snow- 

 bedding was horizontal ; and almost perpendicularly cutting it 

 the structure was visible ; so that we could have wished Profes- 

 sor Tyndall had first sought for it here ; he would have sooner 

 found what he wanted to see. The same was distinctly to be 

 seen abundantly on the Upper Trift Glacier, and even on the 

 little Glarnisch Glacier. 



A second proof of the difference between stratification and 

 the structure, and partly also a support for TyndalFs explana- 

 tion of the origin of the structure, is the following : — I thought 

 to myself, " If a glacier with distinctly developed structure (lon- 

 gitudinal, or much-drawn-out transverse structure) has after- 

 wards to make a fall, the new transverse structure originating 

 at its foot must cut the already present longitudinal structure. 

 Were the structure a stratification, it could not cut itself." The 

 Rhone Glacier, in its upper part, has already the ordinary struc- 

 ture ; we therefore sought at the foot of the fall, in the " struc- 

 ture-mill," for crossed structure. So regularly, however, was 

 the fact not as I had thought, that the masses in the fall 

 tumble into considerable disorder, are many times twisted and 

 dislocated ; the old structure could not be traced throughout 

 its course, but was only partially distinct ; it was often not clear 

 to me whether I had to do with the new or the old. However, 

 after long search and diligent cutting up of the upper white 

 crust (it was a splendid day at the end of summer), we 

 found an immense number of places, scattered over the whole 



