GLACIAL WORK FOR 1842. 365 



their distance from each other. They had 

 also sunk a line of stakes across the glacier. 

 The change in the relative position of the two 

 sets of signals and the curve in their line of 

 stakes gave them, self-recorded, as it were, 

 the rate of advance of the glacier as a whole, 

 and also the comparative rate of progression 

 in its different parts. Great pains was also 

 taken during the summer to measure the ad- 

 vance in every twenty-four hours, as well as 

 to compare the diurnal with the nocturnal 

 movement, and to ascertain the amount of 

 surface waste. The season was an unfavor- 

 able one, beginning so late and continuing so 

 cold that the period of work was shortened. 



