106 Dr. A. Waller's Microscopic Observatio?is on Hail. 



or the ices of pastry-cooks. The others which fell after did 

 not break up in this way. Several of them, examined as be- 

 fore, disengaged, as they melted, bubbles of air in abundance. 

 When the stone was reduced to a thin disc of ice, it became 

 sufficiently transparent to be viewed by transmitted light. It 

 was then perceived to consist of numerous particles of either 

 a globular or ovular shape, closely adhering together, and 

 presenting, on what appeared their surface, numerous very 

 minute black points. The drop of water which resulted con- 

 Fig. 2. 



tained very slight traces of foreign matter of the most minute 

 dimensions. In a few instances I perceived a collection of 

 spherical globules of a green colour about mm, 005. One or 

 two deposited a particle apparently siliceous, which appeared 

 to be in the centre of the hailstone. 



April 3, 2 p.m. — There fell some hail for about five minutes. 

 The weather warm, sun strong, occasional showers during the 

 day. About half an hour previously I observed brilliant, thin, 

 white cirro-strati at various points of the sky : before the hail 

 fell, there appeared a second cloud over head, apparently 

 much lower than the former, very dense and extending rapidly. 

 The first hailstones so completely lost their cohesion and 

 liquefied so quickly, even as they fell on my coat, that I at 

 first took them for drops of rain, with which they were ac- 

 companied. Those which I collected resembled a grain of 

 rice in size and colour. The dark cloud quickly disappeared 

 after the fall of hail ; the upper ones still remained about the 

 same. I had not an opportunity of using the microscope. 



