and Motion of Glaciers. 383 



of M. Agassiz. B and B' are two boxes with sluice fronts, from 

 which the mud flows into the trough. The object was to observe 



Fig. 9. 



the mechanical state of the mass along the line of junction of 

 the two streams, and along their respective centres, and compare 

 the result with the observations upon the glacier itself- The 

 mud was first permitted to flow simultaneously from both boxes, 

 and after it had covered the bottom of the trough to some di- 

 stance below the line ST, the end of a glass tube was dipped 

 into a fine mixture of the red oxide of iron and water, and the 

 two arms of the glacier were covered all over with small circles 

 similar to those between the points ah and a'h'. The mud was 

 then permitted to flow, and the niechanical strains exerted on it 

 were inferred from the distortiou of the small circles. The figure 

 represents the result of tlie experiment. The straight rows of 

 circles bent in the first place into curves ; at the point A both 



