Mr. T. T. P. B. Warren on Electrification. 441 



teorological conditions observed in Georgia during June 1869, 

 and characterized by uncommonly intense frequent rains and 

 thunderstorms. On June 20, a hailstorm, still more violent than 

 those of May 27 and June 6, caused horrible devastations in the 

 valley of Manglis, 18 wersts fromTiflis, and progressed, in the form 

 of rain and electrical discharges, as far as into the valley of Algat. 

 PI. III. figs. 9 and 10 are intended to represent the outlines of two 

 of the most remarkable varieties of hailstones as true to nature as 

 possible, without any pretence to elegant execution. In the two 

 cases under notice, personal observation sets more or less at de- 

 fiance any theory of the formation of hail hitherto established. 

 How could indeed the formation of such crystalline aggregations, 

 as regular as those of the calcareous spars of Andreasberg, be 

 possible in the midst of the tumult generally supposed to 

 be necessarily connected with the formation of hail ? These 

 aggregations may have had a long stay within a medium of 

 highly refrigerated aqueous vapour before they fell to the ground. 

 It must be remarked, to fully understand the drawings, that the 

 shaded portion of the flattened spheroidal fundamental form 

 of the groups is not always opaque in the original. Only the 

 circle round the centre has a milky aspect, due to the air-bubbles 

 enclosed in it, as also the nucleus of the greater number ; in 

 other specimens the nucleus is transparent, especially when re- 

 duced by melting away into disks of j to 1 inch in diameter, 

 sometimes affecting the form of a perfect regular hexagon. In 

 this case the milky circle around the centre appeared distinctly 

 as an intricate tissue of minute lengthened pores and of capillary 

 fissures filled with air. The shadow next to the margin of the 

 larger peripherical circle is only intended to indicate the rounded 

 and flattened spheroidal form of the chief body, on whose broader 

 margin the crystals themselves adhere parasitically, or are in- 

 serted, as in an alveole, made visible by the commencement of 

 fusion (see a in fig. 9). All the specimens presented lengthened 

 vermiform and pyriform pores filled with air, extending radially 

 from the centre to the circumference. The drawing shows these 

 pores of- approximately natural size. 



LIII. On Electrification. 

 By Thomas T. P. Bruce Warren*. 



WHEN an insulated wire or cable is connected to a battery, 

 and the deflection noted on a galvanometer, the first 

 rush of current into the cable is due to the electrostatic capacity 



* Communicated by the Author, having been read at the Exeter Meet- 

 ing of the British Asaociation, in Section A, August 1869. 



Phil. Mag. S. 4. Vol. 38. No. 257. Dec. 1869. 2 G 



