197 



even where the supply of the fluid is uniform ; that this quality is 

 greatly increased when the supply of the fluid is by fits, as it is in fact 

 at the head of this glacier, where the quasi-hydrostatic pressure from 

 behind, combined with the frontal resistance, produces a thickening, 

 or convex lip or wrinkle. 



He likewise mentioned the analogous instance of the production 

 of equidistant wrinkles in the sides of railway banks, from mere 

 pressure above; and more particularly in turnings of coarse mallea- 

 ble iron, where, though the detruding force is constantly equal, still 

 detrusion takes place at intervals, forming in the shaving so many 

 wrinkles, by which frontal resistance too, it is thickened, and conse- 

 quently shortened, similarly with the mechanism of the glacier. 



The Astronomer-Royal, Mr Airy, then favoured the meet- 

 ing with a discourse on the telescopes of Lord Rosse and Mr 

 Lassel, specially pointing out those parts in the progress of 

 construction, in which these two eminent mechanists and opti- 

 cians differed, and sometimes widely, from each other; though 

 they have both arrived equally, at last, at the same goal of 

 all but perfection. 



The following Donations to the Library were announced : — 



Die Fortschritte der Physik im Jahre 1846. Dargestellt von der 



Physikalischen Gesellschaft zu Berlin. 2 Jahrgang. 8vo. — 



By the Society. 

 Medico-Chirurgical Transactions. Vol. XXXI. 1848. Bvo. — By 



the Society. 

 Troisi^me, Cinquieme, Sixieme, et Septieme Memoires sur Tlnduc- 



tion. Par M. Elie Wartmann. 8vo. — By the Author. 

 The Ethnological Journal, No. 7. Dec. 1, 1848. 8vo. — By the 



Editor. 



