Xvi RECENT PROGRESS OF THE GLACIER THEORY. 



deliberate consideration of the whole of my views respecting it. 

 would materially modify. I hope I may be allowed to say that 

 the event has proved, partially at least, that I judged rightly. 

 It was natural that the author of so interesting an experiment 

 as the moulding of ice at a fusing temperature under Bramah's 

 press, should see in it the germ of a new theory. It is not less 

 natural that I, who rather hoped for than expected such a pal- 

 pable illustration of my opinion, should see in it, not a new 

 explanation of the phenomena of glaciers, but a new proof that 

 the explanation which I had advanced was correct. 



These are points which naturally fall to be decided by those of 

 the scientific public who contemplate the question from an impar- 

 tial point of view. If the aspect in which I regard it be the 

 more correct if the conclusions of Dr. Tyndall are rather con- 

 firmatory than subversive of my own the result of the discus- 

 sion will be one more affecting personal credit than scientific 

 truth. If it be found that the limited plasticity of ice, 

 which, when ice is exposed in the glacier to a peculiarly violent 

 strain, necessitates the formation of an infinity of minute 

 rents, is really a part of my theory : that it also embraces the 

 substitution of the finite sliding of the internally bruised sur- 

 faces over one another under the same circumstances, still pro- 

 ducing a quasi-fluid character in the motion of the whole : if 

 it be granted, moreover, that the reconsolidation of the bruised 

 glacial substance into a coherent whole may be effected by pres- 

 sure alone acting upon granular snow or upon ice softened by 

 imminent thaw into a condition more plastic than ice of low 

 temperature, and that the terms " bruising and re-attachment," 

 " incipient fissures reunited by time and cohesion," were equiva- 

 lent in 1846 to the phrase "fracture and regelation " applied 



* The following are specimens of the phraseology used by me in that year, or 

 previously, with reference to the pages where they will he found in the present 



