172 Beport of the Hesearches o/M. Agassie, 



admitting the slow and gradual movement, ascribed it to the 

 infiltration and congelation of the water contained in the ca- 

 pillary fissures. Gruner believed the movement less regular, 

 and that it was determined by the weight of the mass, and by 

 the melting of its sides. De Saussure very much adopted the 

 same view. " These icy masses," he remarks, '* descending 

 the slope of the bed on which they rest, released by the streams 

 from the hold they might take upon this same bed, sometimes 

 even uplifted by this water, must gradually glide and descend 

 in the course of the slope of the valleys, and of the ridges 

 which they cover." Such, too, is nearly the opinion of Kuhn 

 that observer who, of all others during the last century, best 

 comprehended and described the whole phenomena of glaciers. 

 One thing is very clear, that no one in Switzerland ever doubt- 

 ed that the glaciers were subject to movement. And not- 

 withstanding, the fact in itself is not so simple as it appears 

 to those of us who are familiar with it as a matter of public 

 notoriety. It is thus highly interesting to rend over the con- 

 troversies which the inquiry occasioned towards the close of 

 the last century. One of the Professors of the University of 

 Tubingen, M. Plouquet, undertook an excursion into Switzer- 

 land, for the purpose of studying the subject of the glaciers. 

 When he beheld these immense masses, covering whole leagues, 

 and occupying all the sinuosities of the valleys, he could not 

 imagine that they were subjected to any movement whatever ; 

 and he remarked that, if possessed of a gliding motion, they must 

 long before have invaded the plains and valleys into which they 

 debouched. Hence this author thought that the glaciers were 

 immovable, and that if a movement were possible, that move- 

 ment must needs be very slow and gradual ; but as such a 

 motion appeared to him in the highest degree unlikely, he as- 

 sumed that glaciers in general are stationary, and have ever 

 been so. This opinion, published in the year 1786 un- 

 der the title of VertrauUche Erzcehlung einer Schiveizer 

 Reise, roused noisy clamours among the Swiss savans, who 

 regarded it as a decided heresy. Hopfner's Magazine, a dis- 

 tinguished scientific journal which appeared at this time at 

 Zurich, headed the defence ; and M. Kuhn undertook, in 



