152 DR. R. ANGUS SMITH ON A 



sidered that they were in diameter about T ^ to -^hj °f 

 an inch. This could not be determined at the time ; but 

 I remembered the size very well, and measured a body 

 which I considered about the same when I came home. 

 I also obtained the particles spoken of by Saussure exactly 

 in the way he obtained them, and came to the same con- 

 clusion as to their size, but was equally certain that those 

 of the fog were entirely different, being at least ten times 

 as much in diameter. These particles, when seen through 

 a glass, were perfectly spherical, and seemed quite concrete, 

 as Saussure would say, or solid, as some people would re- 

 mark — although this word has a different meaning when 

 applied to water ; in other terms, they seemed to be similar 

 throughout, without any hollow centre. The sun was not 

 down, the sky was still brilliant; and indeed this bril- 

 liancy and the colour of the clouds towards the Occident 

 did not leave as late as 1 1 \ o'clock, and I do not see any 

 reason to suppose that it left at all ; it probably was seen 

 till the sun rose. The light was reflected from some of 

 the spheres in the extreme of the fog, and from some 

 not ; but all seemed concrete, and, being transparent, had 

 a very beautiful appearance. They all tended downwards ; 

 they were falling evidently; it was a falling dew, or a 

 slight incipient rain, rapidly disappearing into the earth. 

 A few globules of air might be entangled in the vapour — 

 of course without systematic vesiculation, a most difficult 

 thing to imagine. It seemed evident to me that to make a 

 distinction absolute between fog, rain, and dew was a waste 

 of words. There is a broad observable distinction, but no 

 narrow line ; and we cannot tell the end or beginning of 

 either. 



Holding that the opinion regarding vesicles rests on a 

 foundation too weak to be worth much attention, I do not 

 consider it necessary to examine the history of the subject 

 with great minuteness. However, as it is not well known, 



