392 Intelligence and Miscellaneous Articles. 



specimen was obtained from the Lower Chalk of Folkestone, about 

 10 feet above the Chalk Marl. 



13. " Rodentia of the Somerset Caves." By W. Ayshford San- 

 ford, Esq., F.G.S. 



The author has examined the Rodents from the caves of Somer- 

 setshire contained in the Taunton Museum, and found that many 

 of them cannot be referred to species hitherto regarded as belonging 

 to the fauna contemporary with the Mammoth in Britain. He enu- 

 merated species of Arvicola (including A. glareola, Schreb., and A. 

 ratticeps, Bias. = Lemmus medius, Mlson, and a species which may 

 be new, and for which he proposed the provisional name of A. 

 Gulielmi), Lemmus (L. norvegicus, Desin.), Lagomys (L. spelceus, 

 Owen), Lepus (L. diluvianus, Pict., L. timidus, Linn., L. hibernicus, 

 Bell, and L. cuniculus, Linn.), Spermophilus ($. erythrogonoides, 

 Falc. : the citation of S. citillus by the author and Mr. Boyd Daw- 

 kins is founded on a mistake), and Cricetus (C. songarus, Pall.). 



LVII. Intelligence and Miscellaneous Articles. 



ON A NEW KIND OF ELECTRICAL DUST-FIGURES. 

 BY PROFESSOR VON BEZOLD. 



TT is a well-known fact that when two glass plates, coated on one 

 •*- side only, are placed with the uncoated sides at a moderate dis- 

 tance apart, while the coated sides are connected with the poles of a 

 Ruhmkorff's coil, a luminous phenomenon is observed as soon as the 

 apparatus is set to work. 



This is a case of discharge produced by influence, and taking place 

 between two non-conducting surfaces, just as in Gassiot's tubes ; 

 in which the same phenomena are observed as in Geissler's tubes, 

 although the enclosed gas is not in direct contact with the polar wires. 



It appeared interesting to investigate whether the consequences of 

 such a discharge produced by induction between insulating surfaces 

 could be made visible by fine powder, in the same manner as Lich- 

 tenberg demonstrated the passage of electricity between a metal and 

 an insulator, and as Kundt has recently shown between two me- 

 tallic electrodes. 



My idea was completely confirmed, and it was observed that figures 

 of great regularity may be obtained in the way in question. I will 

 give the principal experiments here. 



On the edge of a glass plate with a circular coating underneath, 

 three small pieces of glass of 1*6 million, thickness were laid, and 

 on these was placed, with its uncoated side downward, a plate quite 

 similar to the first. The lower plate was strewn with lycopodium 

 powder. 



When, now, the lower plate was connected with the positive, and 

 the upper with the negative pole of a large Ruhmkorff's coil which 

 was worked by a single element, and the action continued for about 

 a minute, on removing the upper plate it was found that about half 

 the powder had been projected against it, and that it formed very 

 characteristic figures upon each. 



The entire upper plate was covered with small circles which were 



