1846.] LAWS OF MOTION OF A SMALL GLACIER. 119 



XIV. ILLUSTRATIONS OF THE VISCOUS THEORY 

 OF GLACIER MOTION. PART III.* 



6. On the Motion of Glaciers of the Second Order. 7. 

 On the Annual Motion of Glaciers, and on the Influence of Seasons. 

 8. Summary of the Evidence adduced in favour of the Theory. 



6. ON THE MOTION OF GLACIERS OF THE SECOND ORDER. 



Up to the year 1844 no attempt had been made, so far as 

 I am aware, to measure the rate of motion of those compara- 

 tively small isolated glacial masses reposing in the cavities of 

 high mountains, or on cols, called by De Saussure Glaciers of 

 the Second Order. 



Some observations had indeed been made upon a glacier of 

 this description in 1841, and by MM. Martins and Bravais, 

 during a residence on the Faulhorn. But it was not at that 

 time known that the motion of glaciers was a continuous and 

 regular one, admitting of rigorous measurement even in short 

 intervals of time, and the importance of such observations was 

 overlooked. They accordingly believed that the glacier in 

 question had no sensible motion, and probably they did not 

 attempt to observe it until a subsequent year. It is impossible 

 now to doubt that the Blau Gletscher, near the Faulhorn, has a 

 movement like all other bodies of the kind. 



In July 1844, I had an opportunity of passing some days 

 at the hospice of the Simplon, in the neighbourhood of which 

 exists a small glacier of the second order, easy of access, and 

 very fit for the experiment which I proposed to myself upon 

 such bodies. Its diminutive size made it all the more suitable ; 

 for should it be found to possess a regular motion, we are 

 certain that the mechanism of a glacier is contained! within the 

 small compass of a mass which may be conveniently examined 



* [Philosophical Transactions, 1846, p. 177.] Received January 27, Read 

 February 26, 1846. 



f [Misprinted continued^] 



