D. L. Cosari on Remarkable Hailstones. 



87 



above the level of the water, — a fact which proves that the 

 former, composed chiefly of whitish opaque ice, was much more 

 dense than the latter. 



Among all the hailstones which have been examined during 

 and after their descent, not one has been found which gave the 

 idea that it was formed by an agglomeration of several hailstones. 

 It is true there were many of a very irregular form, but even 

 these were composed of a single system of particular and distinct 

 striae. 



Several persons thought that they observed stony or metallic 

 substances descending at the same time with the hail, and there 

 were presented to the author as such, fragments of sulphate of 

 iron, and carbonate of lime, and furnace-made brick. But the 

 manner in which these fragments were procured, did not leave 

 him free from doubt as to their origin, and gave ground for the 

 suggestion that their descent might be owing to the effect which 

 the hail had in detaching from the walls and roofs on which it 

 beat, those fragments which were thus collected. 



In the interior of a great number of the hailstones, there was 

 noticed a heterogeneous and sandy matter, which was there dis- 

 posed, in a manner more or less regular, round the centre. Un- 

 fortunately, none of the individuals who particularly observed 

 this, thought of examining or preserving any of it. The author 

 himself remarked only two hailstones which appeared to enclose 

 any foreign matter. In the one, these substances were exactly 

 in the centre, and in minute quantity. In the other, the nucleus 

 was of an ash-colour, and about the third of an inch in diameter. 

 On removing the external layers from the hailstone, to the ex- 

 tent that the nucleus was only surrounded by pure ice, he ob- 

 tained a residue of a light greyish powder, in so small a quantity 

 that it scarcely stained the linen-cloth he employed to collect it. 

 He subjected this powder to the examination of a strong magni- 

 fying-glass, and he distinguished that some grains were larger 

 than the rest, though they had the same clear yellow colour, and 

 the same resemblance to sulphate of iron. Some of the grains, 

 which were of a blackish-grey colour, were attracted with the 

 greatest facility by the loadstone. The very minute dimensions, 

 and the extremely small quantity of this dust, which M. Cosari 

 had procured, led him to abandon the determination he had at 



