Account of some remarkable Hail-Stones . 327 
rradii. Fig. 1. PL IX. represents the cerebral form of the hail- 
stones. Fig. 2. is the section of a hail-stone, shewing the con- 
centric lamellar structure and the beautiful radiation. Fig. 3. 
is one of the hail-stones cut in the direction of a shorter axis. 
Captain Delcross, in the 13th volume of the Bibliotheque 
Universelle , describes hail-stones having the concentric lamellar 
structure and stellular fibrous arrangement. Fig. 4. is a sec- 
tion of one of the hail-stones observed by Delcross. In it the 
concentric lamellar structure is not so distinctly shewn as in the 
figures given by Nogerath, owing to the circumstance of the 
drawing having been made by candle-light, when the structure 
is not so well seen. In the hail-stones examined by Del- 
cross, the surface, as represented in Fig. 4., was provided with 
pyramidal forms, whose summits are already blunted by inci- 
pient melting ; whereas, in the hail-stones examined by Nbge- 
rath, the surface was covered with irregularly grouped segments 
of balls. When the edges and angles of the pyramids are melt- 
ed down, the cerebral form is produced ; when the masses of 
hail, having the structures described, burst asunder, the frag- 
ments have a pyramidal form, as represented by Figs. 5. and 6., 
and then forms what has been described, under the name Pyra- 
midal Hail . 
In a letter addressed to P. Neill, Esq., by Robert Lindsay, 
Esq. of Aberdeen, and read before the Wernerian Society on 
29th November 1823, there is an interesting account of a hail- 
storm, in which some of the hail-stones had a pyramidal form. 
The following is an extract from the letter : 
44 During Thursday the 27th of June (1823), the sky had, for 
the greater part of the day, been overcastwith large compact white 
clouds, such as in winter are thought to threaten snow, in sum- 
mer thunder, and which have been very frequent during what 
is past of this cold summer with us. There was also a lower 
range of a darker hue, which had given us a few slight showers, 
and some large hail-stones. The wind had blown for a number 
of days from NW. or thereabout. Between 1 and 2 p. m. it 
veered about by W. to SE. The clouds, however, continued 
throughout the evening from NW. 
$ 4 At 5 p. M. fell a shower,— at first large drops of rain as for- 
merly, and in a short time a violent hail-shower. The regula- 
