ATMOSPHERIC DUST IN" THE ARCTIC REGIONS. 155 



of the same species on the alpine peaks of California, 

 Colorado, and Switzerland. But the atmospheric aspects 

 were new and strange, and at times fascinating. They showed 

 themselves in the character of the rains and fogs, in the 

 aspects of the sky and the landscapes, and in the mirages 

 seen over the water. 



The rains and fogs, arid other atmospheric phenomena of 

 that portion of the North which we visited, were just such as 

 we might infer from the paucity of smoke and dust in the air 

 there. Over the millions of square miles within the Arctic 

 Circle practically no smoke is generated, and but little for 

 many more millions lying in the high latitudes surrounding 

 it. All the other sources of dust are scanty, and most of that 

 which is wafted to the regions from more southern climes is 

 washed out rapidly by the abundant rains and fogs. From 

 the nature of the case, the difference between the air-temper- 

 ature and the dew-point can never be so great as it is in our 

 latitude. 



It was evident from the character of both the fogs and 

 rains that there was a paucity of dust-particles in the air for 

 the water to condense upon. None of the fogs seen north of 

 latitude 52 or 53 are so white and opaque as those which 

 are common south of latitude 50. There is much exaggera- 

 tion in the popular description of fogs. We often hear 

 them described as being so thick that nothing can be seen 

 a hundred feet away. In fact, such fogs are rare, on sea or 

 land. Comparatively few fogs are so opaque that large dark 

 objects cannot be seen through them two hundred feet. I 

 saw none in the Greenland seas through which we could not 

 see several hundred feet, and usually very much farther. The 

 fogs were all much more transparent than those we met with 

 off the coast of New England and Nova Scotia on our voyage 

 both out and back. They were, however, as a rule, very 

 much wetter, and more misty. Often, when the fog was so 



