CLOUDS AND EIYEES, ICE AND GLACIEES. 79 



the maximum motion at the Montanyert being fourteen 

 inches a day greater than at Trelaporte. 



§ 27. ^Motion of Tributary Glaciers. 



194. So much for the trunk glacier; let us now 

 investigate the branches, permitting, as we have hitherto 

 done, reflection on known facts to precede our attempts 

 to discover unknown ones. 



195. As we stood upon our ' cleft station/ whence 

 we had so capital a view of the Mer de Glace, we were 

 struck by the fact that some of the tributaries of the 

 glacier were wider than the glacier itself. Supposing 

 ,vater to be substituted for the ice, how do you suppose 

 it would behave ? You would doubtless conclude that 

 the motion down the broad and slightly-inclined valleys 

 of the Geant and the Lechaud would be comparatively 

 Blow, but that the water would force itself with increased 

 rapidity through the ' narrows ' of Trelaporte. Let us 

 test this notion as applied to the ice. 



196. Planting our theodolite in the shadow of Mont 

 Tacul, and choosing a suitable point at the opposite side 

 of the Glacier du Geant, we fix on July 29 a series of 

 ten stakes across the glacier. The motion of this line 

 ji twenty-four hours was as follows : — 



MOTION OF GLACIER DU GEANT. 



Sixth Line: HH' rrox Sketch. 



Stake ..123456789 10 



Inches , . 11 10 12 13 12 13 11 10 9 6 



