Intelligence and Miscellaneous Articles. 541 



Lyelli also occurs at this level. Above the greensands come 6 feet of 

 chloritic marl : — the upper 3| feet fossiliferous, with a base of hard 

 phosphatic nodules containing crushed specimens of Pecten asper; 

 the lower 2j feet compact, with darker grains and few fossils. The 

 author compared the sections of this series given by Capt. Ibbetson 

 and Dr. Barrois ; his own views closely correspond with those of the 

 latter writer. 



2. "On the Flow of an Ice-sheet, and its Connexion with 

 Glacial Phenomena." By Clement Reid, Esq., F.G.S. 



The author considers that the Boulder- clays have been formed 

 beneath an ice-sheet, and consequently there must have been 

 formerly a huge mass of ice, which would have to flow 500 miles 

 on a nearly level surface, and then to ascend a gentle slope for nearly 

 another 100 miles. He does not think a great piling up of the ice 

 at the north pole can be assumed to account for this motion. This 

 he explains by the gradual passage of the earth's heat through the 

 mass of ice raising the temperature of the whole instead of lique- 

 fying the surface-layer. As the heat passes upwards it raises the 

 temperature of a particular layer, causes it to expand, and so to put 

 a strain upon the layer above, and then to rupture it. The broken 

 part spreads out, reunites by regelation, and then, receiving the heat 

 from the layer below, again expands, and ruptures the layer next 

 above. Thus the movement is from the base upwards, rather than 

 from the surface downwards. 



The author estimates that the ice-sheet in Norfolk was only about 

 400 feet thick, because Boulder-clay does not appear above that 

 level, but only coarse Boulder- gravel ; in North Yorkshire it extends 

 up to about 900 feet. The author considers that the shell-beds of 

 Moel Tryfaen were not deposited under water, but thrust up hill by 

 this advancing ice-sheet. 



3. " Soil-cap Motion." By R. W. Coppinger, Esq. 



The author described numerous cases in Patagonia where the 

 stumps &c. of trees are to be seen in the marginal waters of the sea 

 and of lakes. These, together with stones and rocks, sometimes 

 simulating perched blocks, he considers to have been brought down 

 by the motion of the soil-cap — a thick spongy mass resting upon 

 rock often worn smooth by the action of ice, and so sliding down 

 the more easily under the influence of vegetation. The appearances 

 are not unlike those due to subsidence ; but he points out that all 

 the evidence is in favour of recent upheaval, instead of subsidence. 



LXXIII. Intelligence and Miscellaneous Articles. 



ON THE INTERNAL DISCHARGES OF ELECTRICAL CONDENSERS. 

 BY E. VILLARI*. 



WHEN a strongly charged battery is discharged, a characteristic 

 rumbling noise is produced in its interior ; the glass of the 

 jars becomes brightly luminous at the edges of the coatings ; and 



* Atti delV Ace. della Soc. di Bologna, 11 Nov. 1880, ser. 4, voL ii. 1881. 

 Phil. Mag. S. 5. No. 71. Suppl. Vol. 11. 2 Q 



