real Sii'actare of Glacio' Ice 151 



verrez par la que si vous avez pu croire avoir fait une decouverte a ce 

 sujet, ce n'a pi. etre qu'en mecomprenant ce que j'ai pii vous dire* sur la 

 profondeur a laquelle ces lames desccndcnt, et qui n'avaient ete remar- 

 quees qu'a une faible profondeur avant 1841, et par moi seulement dans 

 le voisinage des moraines. 



[Here follows tbe Letter, and Extract Eleventh.'] 

 « Jugez maintenant si j'ai du etre surpris de vos reclamationst et si 

 j'etais en droit d'y rcpondre comme je I'ai fait. N'ayant pas I'habitude 

 "de tenir un journal regulier des moindres particularite's des observations 

 que je fais, ct addressant dans nos societes scientifiques toutes mes com- 

 munications de vive voix, ces faits ne me sont revenus a moi-meme avec 

 les circonstances accessoires que lorsquc mes amis me les ont rappele's. 

 ***** 



"Nevfchatcl, 28 Aviil 1842." 



After receiving the preceding letter, I gave up all thoughts 

 of attempting to convince M. Agassiz respecting the history 

 of this, or indeed of any, scientific question. In the course 

 of a few months, he had entertained four different opinions 

 respecting the authorship of the discovery in question, and 

 still, I suppose, has some doubt as to whether he disco- 

 vered it himself in 1838, or only in 1841 ; or whether he 

 learned it from M. Guyot at Porrentruy, or from me at the 

 glacier of the Aar. 



The structure in (luestion, which is common to every glacier 

 in which I have looked for it, is in some so exceedingly strik- 

 ing, that it would seem impossible to escape notice. Such, 

 for instance, is the case with a glacier of great beauty and 

 extent, and which is remarkable from being almost touched 

 by a frequented mule-road, whence the structure is admirably 

 seen,— I mean the glacier of La Brenva, near Courmayeur. 

 That it has not been described by any of the modern writers 

 on glaciers, De Saussure, De Charpentier, Hugi, Agassiz, or 



* See Extract Second for M. Agassiz' own account of Avhat he did tell 

 me of bis previous observations. 



t Of course I maintain th^it he had no right whatever to be surprised, smce 

 it appears from the following sentence, that he was equally ignorant with 

 myself of what he had himself done in 1838, until receiving M. Dubois' 

 letter, dated the day before this was written :— " Ces /ails ne mc sont reve- 

 nus a moi-mc.M avec Us circonslamcs acceinoires que lorsque met amis me 

 les oui raiipcUs." 



