Professor Hiigrs Observations on the 



rowed. I have never been able to discover at the interior a 

 regular crystalline contexture. It is to be remarked, that it is 

 only in detached blocks, 'or on water sheds, and never in the in- 

 Iterior of a compact glacier, that the crystals separate of them- 

 selves and fall into a heap." -;^ 

 ■ " I have had an opportunity of examining the inferior suTis 

 face of many glaciers of the second kind, such as those oft 

 Uraz, of Viesch, of Munster, the superior glaciers of the 

 Aar, and of Grindelwald. This surface is continually melt^ 

 ing;'it exhibits sorts of domes or vaults, and the glacier rests 

 on the rock only by some insulated feet. The ice is very 

 smooth ; traces of the joints of crystals marking it like net- 

 work on the exterior ; the ice is melted more deeply on these 

 traces than elsewhere. As to the superior surface, it is, on the 

 contrary, very rough, the fusion is, in this case, deeper at the 

 junction of the crystals, so that they form many protuberances. 

 The ice at the interior and exterior, where there is a low tem- 

 perature, or after a very cold night, exhibits but in an imperfect 

 manner the forms of crystals which we are describing; and its 

 aspect again approaches that of compact ice. But if some co,^ 

 loured acids be poured on it, or alcohol, there appears instantly 

 a cellular tissue delineated on its surface, which makes the out- 

 line of each crystal appear. If a salt be employed, the mass 

 commences to decrepitate, and the form of the crystals is bet- 

 ter defined. 



The ice of the glaciers of the second kind contains, like ordi- 

 nary ice, a great number of vesicles. AVhen those vesicles are 

 terminated in a sharp point, I have found, in melting the ice 

 under water, that they do not contain air ; whilst, if they are 

 rounded, which rarely happens when they are opened with a 

 needle, or melted under water, they disengage air. The ice of 

 a glacier of the first kind is much richer in gaseous matters, 

 which are probably nothing else than atmospheric air, which ap- 

 pears to be, in this case, the agent of transformation ; the air and 

 the ice have a reciprocal action, from which it results, that the 

 ice, after having decomposed and solidified the air, passes itself 

 into that state wherein it constitutes glaciers of the second kind. 

 The sharp-pointed vesicles have always the apex ^jipfeiji^^^ 



-a 'jiii m ?H*.^^ 



