Scientific Intelligence. Meteorology. 389 



9. Observations made on the occasion of two Hailstorms 

 which occurred at Toulouse and Jouzac. The former occurred 

 on 8th of July 1834. By Mr Prof. Boisgeraud. The form 

 and the structure of these hail-stones, says the author, was very 

 remarkable. All that I examined, without exception, had an 

 interior nucleus. These nuclei were generally roundish, al- 

 though I also remarked some which were flat. Their diameter 

 was usually about two-fifths of an inch, though I found some 

 equal to three-fifths. In the majority of these nuclei, the centre 

 was occupied by a small opaque white ball, like snow. This 

 little ball was sometimes reduced to a white point ; to which 

 succeeded concentric layers, alternately limpid and translucent. 

 When these nuclei were divided into two, and polished on a 

 plain surface, having a temperature superior to the freezing 

 point, the section presented the appearance of some polygonal 

 agates. It certainly did not appear to me that these layers 

 were formed by successive additions of matter, and that it 

 was possible to effect their separation : the very reverse ap- 

 peared to be the truth the whole hailstone appeared to be 

 formed at a single instant, and I found it quite impossible, not- 

 withstanding all my endeavours, to succeed in discovering any 

 natural divisions between these different layers, by which to se- 

 parate them. It is quite apparent to me that such divisions do 

 not exist, and that the formation of the layers was not conse- 

 cutive. By breaking these nuclei with the teeth, the interior 

 exhibited a texture which was radiated from the centre quite to 

 the external surface. This arrangement, which could also be 

 perceived in the entire hailstone, seems also to be opposed to 

 the idea of their increase by the successive deposition of layers. 

 The snowy layers of the hailstone frequently enclosed minute 

 air-bubbles, which were visible to the naked eye : they were of 

 different volumes, and sometimes very small and very numerous. 

 Some portions formed very minute lamina?, and then 4he hail- 

 stones were iridescent. When the air-bubbles were considerable 

 in number and size, the hailstone was friable. The exterior of 

 the hailstones was very angular ; and many of their acute points 

 were eight-tunths of an inch long, and some even more than an 

 inch. These transparent points were in every respect an inte- 

 gral part of the hailstone: it was impossible to break them off 



VOL. XXII. NO. XL1V. APRIL 1837- C C 



