. MOTION OF GLACIERS DES BOIS AND BOSSONS. 
185 
general accordance is sufficiently manifest, and the effect of the season of the year 
is beautifully shown, the following being the minimum and maximum values : — 
Daily motion in inches. 
Glacier des Bois, No. I., minimum in December 11*5 
Glacier des Bois, No. I., maximum in July 52-1 
Ratio of maximum to minimum . . . . 4 \ : 1 
Glacier des Bois, No. II., minimum in January 2 6 
Glacier des Bois, No. II., maximum in July 14‘6 
Ratio of maximum to minimum . . . .5^:1 
Glacier des Bossons, No. I., minimum in March 12 9 
Glacier des Bossons, No. I., maximum in May 42 9 
Ratio of maximum to minimum . . . .3^:1 
Glacier des Bossons, No. II., minimum in March ..... 10-2 
Glacier des Bossons, No. II., maximum in June 32*3 
Ratio of maximum to minimum . . . .3^:1 
From these observations we may deduce the annual motion from November 1844 
to November 1845 with considerable exactness. Allowing for the fractional parts 
of a year, we obtain the following results, amongst which I have included a separate 
computation of the mean daily motion for the summer period (April — October), and 
the winter period (October — April). 
Table V. 
Bois, 
No. I. 
Bois, 
No. 11. 
Bossons, 
No. I. 
Bossons, 
No. II. 
Motion for 365 days, November 1844 to November 1845. . . . 
Mean daily motion 
feet. 
847*5 
inches. 
27*8 
37*7 
19*1 
2*0 : 1 
feet. 
220*8 
inches. 
7*3 
9*9 
4*7 
2*1 : 1 
feet. 
657*8 
inches. 
21*6 
28*0 
15*8 
1*8 : 1 
feet. 
489*1 
inches. 
16*1 
22*2 
io*7 ! 
2*1 : 1 
Mean daily motion, summer period, April to October 
Mean daily motion, winter period, October to April 
Ratio, summer: winter, motion 
I. From this Table we deduce in the first place a mean annual motion far greater 
than has hitherto been observed, or perhaps suspected in any glacier, that of near 
300 yards, or almost one sixth of a mile. This is on the Glacier des Bois beneath the 
Chapeau , where the inclination of the glacier is very steep, adding a new illustration 
of the general principle*, that in similar circumstances the velocity increases with 
the slope. To this cause may be added the high temperature of the air of the valley 
to which in this part of its course it is exposed ; but this last cause is alone insuffi- 
cient ; for 
II. We find that the lowest part of the same glacier immediately behind the Cote 
* Travels, 2nd edit. p. 371. 
2 b 2 
