HALF A CENTOflY AGO AND TO-DAY. 



23 



Rate of motion of the Mer cle Glace. 

 (Speed in centimetres.) 



Years. 



EciIELETS, 



MONTANVERT. 



Mauvais-Pas. 



Chapeau. 



Rate. 



Slope. 



Rate. 



Slope. 



Rate. 



Slope. 



Rate. 



Slope. 



1891-2 



390 



6-2 



44-0 



11-5 



36-0 



8-4 







1 892-3 



39-3 



5'5 



44-1 



15-1 



35-5 



12-4 







1893-4 



38-1 



2*7 



40-6 



145 



34-2 



14-6 



43-4 



50 



1 894-5 



34-0 



8-5 



32-9 



15-2 



30-7 



10-8 







1895-6 



31-7 



10-0 



28-9 



10-7 



30-8 



38-7 







1896-7 



32-6 



10-8 



28-3 



9-7 



30-8 



38-7 







1897-8 



33-5 



7-3 



27-7 



11-6 



31-0 



39-6 







1898-9 



34-4 



7-2 



26-3 



10-2 











Amongst other results arrived at by this observer were that the 

 rate of motion of the ice is greatest in summer and least in 

 winter. Tliis is true of all the Alpine glaciers, and has been 

 determined by Streenstrap even regarding the ice of Greenland. 



Observations on the ''ablation" of the Mer de Glaee. — Mons. 

 Yallot has also contributed an interesting " note " to the French 

 Academy on the " ablation " or lowering of the surface of the 

 Mer de Glace during two definite periods, namely, 15 and oT 

 years, at stages given in the above table : — 



{The figures arc given in metres.)* 





Altitude. 



Years. 



Exact mean. 



Approximate- 

 in 57 years. 



At Echelets 



1,920 



15 



11-0 



54 



„ Moiitaiivert... 



1,843 



14 



13-4 



55 



„ Maavais-Pas 



1,705 



13 



19-8 



49 



„ Chapeau 



1,550 



13 



29-5 



74 



Thus at Echelets, the highest of these stages, the lowering of 

 the surface has been in 15 years 36'08 feet, and in 57 years 

 177*12 feet ; while at Chapeau, the lowest of the stages, the fall 



Dated June 22nd, 1908 ; the figures are in metres 



C 



