SUMMER OF 1842 ON THE GLACIER. 351 



Mr. Wild, an engineer of known ability, 

 was now a member of their party, as a topo- 

 graphical survey was to be one of the chief 

 objects of the summer's work. The results of 

 this survey, which was continued during two 

 summers, are embodied in the map accom- 

 panying Agassiz's " Systeme Glaciaire." Ex- 

 periments upon the extent and connection of 

 the net-work of capillary fissures that admit- 

 ted water into the interior of the glaciers, oc- 

 cupied Agassiz's own attention during a great 

 part of the summer. In order to ascertain 

 this, colored liquids were introduced into the 

 glacier by means of boring, and it was found 

 that they threaded their way through the mass 

 of the ice and reappeared at lower points with 

 astonishing rapidity. A gallery was cut at a 

 depth of ten metres below the surface, through 

 a wall of ice intervening between two cre- 

 vasses. The colored liquid poured into a hole 

 above soon appeared on the ceiling of the 

 gallery. The experimenters were surprised to 

 find that at night the same result was obtained, 

 and that the liquid penetrated from the surface 

 to the roof of the gallery even more quickly 



boulder still contributes something toward the sequel of the 

 work begun by those who once found shelter beneath it. 

 E. C. A. 



