real Structure of Glacier Tee. 145 



at Porrentruy, but was published neithei" at large nor in 

 abstract. It appears to have dropped not only out of the 

 records of the meeting, but from the minds of those who 

 were present, since M. Agassiz, whom it was specially cal- 

 culated to interest, takes no notice of it in his book, published 

 two years later, containing his own observations, already 

 quoted, on the superficial striae ; which he could not in com- 

 mon fairness have published without mentioning M. Guy- 

 ot's contemporaneous and far more important observation of 

 the structure, of which these striae are only the outward in- 

 dication, had he been acquainted with its true bearing, or, 

 in truth, had he recollected it at all. Be this as it may, it 

 seems that i\I. Guyot himself never repeated the observation, 

 and, so fur as it appears, never even spoke of it, between the 

 meeting at Porrentruy in 1838, and his hearing, first at Gene- 

 va in October 1841, then at Neufchatel in November, M. Agas- 

 siz' account of his " new fact." M. Guyot has most honour- 

 ably testified to me* that not one word had ever passed between 

 himself and vie, which could have informed me of what he al- 

 ready knew on the subject; and, also, that he twice traversed 

 the Glacier of the Aar, on the 18th and 19th of August 1841, 

 witiiout noticing or recognising the structure which he had him- 

 self described. I mention this, because M. Agassiz has thought 

 it necessary to assume that the Glacier of the Aar was more 

 distinctly veined in 1841 than in any of the previous years 

 that he visited it, in order to account for his not having noticed 

 it until he returned to the glacier in my company. In the 

 Edinburgh Philosophical Journal for October last, page 266, 

 he says, — "During the months of August and September 1841, 

 this phenomenon was so well developed in the Glacier of the 

 Aar, that it could not fail to strike every ohserverT 



M. Guyofs next step was a perfectly natural and just one. 

 Finding that his original observation had been totally for- 

 gotten, he reproduced his paper from his bureau, where it still 

 remained in MS., and read it afresh before the Societe des 

 Sciences Naturelles at Neufchatel, on the 1st December 1841, 

 just five days before I was similarly engaged, not merely in 

 claiming for myself, before the Royal Society of Edinburgh, 



* In :i liCttcr dated 3d June 1842, in answer to niiiio in Exlrnrt TmlJi. 



VOL. XXXIV. N'O. LXVII. .TANIfARV 1843. K 



