5W Professor Hugi'^s Olservattms on the 



Mwile, blocks of ice more than twenty feet high, placed so that 

 their strata were vertical. When the exterior stratum began to 

 be decomposed by the action of the solar rays, I easily detached 

 a whole stratum by means of a hammer, or with my mountara- 

 poll : it shook like a wall and fell into pieces ; T was in danger 

 of being crushed by the unexpected fall of this mass. After- 

 wards^ in proportion as each of the consecutive strata began to 

 be decomposed, at the same time it begdn to bend, and sodri 

 afterwards it fell. At the extremity of some glaciers, the dust 

 and earthy matters form blackish lines, which trace the limits of 

 the strata. When this is not the case, the arrangement, which 

 is most frequently horizontal, is easily discovered by means of 

 the hammer. The superior strata are generally from half a 

 foot to a foot in thickness ; this thickness increases with the 

 depth, so that in the great glaciers, the thickness of the lower 

 strata may amount to about eight feet. The only glaciers 

 which form an exception, are those which are broken on the 

 rocks, and are formed again lower down ; these are subject tb 

 no rule. In the small glaciers, which extend less towards the 

 base, the inferior strata differ less from the superior. These 

 facts agree with the increase of the crystals, and with the gra- 

 dual extension of the glaciers. In general, the strata are pa- 

 rallel to the superior surface of the glacier; they only deviate" 

 from it in rare cases, where the inferior vaults have fallen, and 

 where the melting at the bottom has taken place in an unequal 

 manner.'" 



" The colour of the small detached fragments of a glacier, or 

 of an isolated crystal, is decidedly white and clear ; we never 

 perceive any trace of other colours. But if we examine a 

 greater mass, as the thickness increases, it becomes of a blue 

 colour gradually more deep: it is at first a sky-blue scarcely 

 discernible, then a fine enamel-blue, and, finally, a very deep 

 azure-blue. In certain glaciers, there is associated with the 

 aJfure-blue a small tint of sea-green, which sometimes predomi- 

 nates. In some places, and especially in the fissures and cre- 

 vices formed beneath by meltingi the gradation of colours which ^ 

 wb'^WP^f^biliitiVjf]^ out is so pure and clear, that we admire it. 

 without beinjr able either to describe or imitate it. Thus we 



discover what is of inrportance, the piass of the glaciers eqrres- 

 noqet B ,*S8r ipsy ^Ai nl ' i>lomJn« snn«m &umm oJ iHofo-^ 



